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METABOLISM  AND  GROWTH 
FROM  BIETH  TO  PUBERTY 


FRANCIS  G.  BENEDICT 

AND 

FRITZ  B.  TALBOT 


PUBLISHED  BY  THE  CARNEGIE  INSTITUTION  OF  WASHINGTON 
WASHINGTON,   1921 


CARNEGIE  INSTITUTION  OF  WASHINGTON 

PUBLICATION  No.  302 


PRESS  OF 

THE  NEW  ERA  PRINTING  COMPANY 
LANCASTER,  PA. 


W5 
103 


METABOLISM  AND  GEOWTH 
FROM  BIRTH  TO  PUBERTY 

BY 

FRANCIS  G.  BENEDICT  AND  FRITZ  B.  TALBOT 


U4168.'} 


CONTENTS. 

PAGE 

Introduction 1 

Basal  metabolism 2 

Previous  studies  of  metabolism  of  children 4 

Control  experiments  and  basal  metabolism 21 

History  and  plan  of  research 25 

Apparatus  and  experimental  technique 28 

Respiration  apparatus 28 

Experimental  conditions 30 

Discussion  of  results 32 

Normality  of  cnildren  studied 33 

Standards  for  determining  the  normality  of  children 34 

Earlier  data  selected  for  comparison  with  our  data 36 

Relationship  between  body-weight  and  age  with  boys 39 

Relationship  between  height  and  age  with  boys 41 

Relationship  between  body-weight  and  age  with  girls 42 

Relationship  between  height  and  age  with  girls 43 

General  consideration  of  the  ratios  of  body-weight  to  age  and  height  to  age  with 

boys  and  girls 44 

Relationship  between  height  and  body-weight  with  boys  and  girls 45 

Growth 47 

Anthropometric  measurements  as  indices  of  growth 52 

Physiological  and  anthropometrical  significance  of  surface  area 63 

Relationship  between  surface  area  and  body-weight,  height,  and  age  with 

boys 63 

Relationship  between  surface  area  and  body-weight,  height,  and  age  with 

girls 66 

Normal,  average,  and  ideal  states  of  nutrition 69 

Body-weight  in  relation  to  height  as  an  index  of  state  of  nutrition 72 

Pulse-rate 75 

Methods  of  obtaining  pulse-rate 77 

Influence  of  age  upon  the  pulse-rate 78 

Average  pulse-rate  of  children 81 

Sex  and  minimum  pulse-rate 83 

Average  pulse-rate  with  increasing  age 85 

Rectal  temperature 85 

Influence  of  food  on  metabolism 89 

The  element  of  novelty  in  measurements  of  metabolism 97 

Metabolism  as  affected  by  growth 100 

General  methods  of  study 100 

Metabolism  during  growth  as  shown  by  the  individual  child 101 

Observations  with  subject.  No.  145 101 

Observations  with  22  children  during  periods  of  4  months  to  3£  years 115 

Metabolism  during  growth  as  shown  by  groups  of  individual  data 128 

Method  of  grouping  data 131 

General  trend  of  metabolism  with  increasing  age 133 

Total  calories  per  24  hours  referred  to  age  (boys) 133 

Total  calories  per  24  hours  referred  to  age  (girls) 134 

Total  metabolism  of  children  referred  to  age  (earlier  investigators) 136 

General  conclusions  as  to  total  metabolism  and  age  in  children 139 

Total  metabolism  with  increasing  body-weight 139 

Total  calories  per  24  hours  referred  to  weight  (boys) 140 

Total  calories  per  24  hours  referred  to  weight  (girls) 141 

Total  metabolism  of  children  referred  to  weight  (earlier  investigators) 142 

iii 


IV  CONTENTS. 

PAGE. 

Metabolism  as  affected  by  growth — Continued. 
Metabolism  during  growth  as  shown  by  groups  of  individual  data — Continued. 

Metabolism  per  unit  of  body-weight  referred  to  age 145 

Calories  per  kilogram  of  body-weight  per  24  hours  referred  to  age  (boys) ...  146 
Calories  per  kilogram  of  body-weight  per  24  hours  referred  to  age  (girls)  . . .  149 
Calories  per  kilogram  of  body-weight  per  24  hours  referred  to  age  (earlier 

investigators) 150 

Metabolism  per  unit  of  body-weight  referred  to  weight 153 

Calories  per  kilogram  of  body-weight  per  24  hours  referred  to  weight  (earlier 

investigators) 157 

Relationship  between  surface  area  of  the  body  and  metabolism 159 

Total  calories  per  24  hours  referred  to  actually  measured  body-surface  area 

(boys) 161 

Total  calories  per  24  hours  referred  to  actually  measured  body-surface  area 

(girls) 164 

Calories  per  square  meter  of  body-surface  referred  to  body-surface 165 

Comparison  of  the  caloric  output  per  square  meter  of  body-surface  with  total 

body-weight 167 

Comparison  of  heat  production  per  square  meter  (measured),  referred  to 

body-weight,  with  earlier  data  (computed) 169 

Age  relations  in  the  heat  production  per  square  meter  of  body-surface 173 

Influence  of  sex  and  sexual  change  on  metabolism 176 

Metabolism  in  prepubescence 183 

The  prediction  of  the  basal  metabolism  of  youth 187 

Predicted  heat  from  total  calories  referred  to  weight  (boys) 188 

Predicted  heat  from  total  calories  referred  to  surface  (boys) 194 

Comparison  of  the  predicted  metabolism  of  boys  and  men 197 

Predicted  heat  from  total  calories  referred  to  weight  (girls) 198 

Predicted  heat  from  total  calories  referred  to  surface  (girls) 203 

Practical  value  of  the  prediction  of  basal  metabolism 205 

The  24-hour  energy  requirements  of  growing  children 206 


ILLUSTRATIONS. 

PAGE 

FIG.     1.  Infant  respiration  apparatus  as  used  at  the  Directory  for  Wet  Nurses 30 

2.  Respiration  apparatus  as  used  for  children  at  the  New  England  Home  for 

Little  Wanderers 30 

3.  Relationship  between  body-weight  and  age  with  boys 40 

4.  Relationship  between  height  and  age  with  boys 41 

5.  Relationship  between  body-weight  and  age  with  girls 43 

6.  Relationship  between  height  and  age  with  girls 44 

7.  Relationship  between  height  and  body-weight  with  boys 45 

8.  Relationship  between  height  and  body-weight  with  girls 46 

9.  Relationship  between  body-surface  and  body-weight  with  boys 64 

10.  Relationship  between  body-surface  and  height  with  boys 65 

11.  Relationship  between  body-surface  and  age  with  boys 66 

12.  Relationship  between  body-surface  and  body-weight  with  girls 67 

13.  Relationship  between  body-surface  and  height  with  girls 67 

14.  Relationship  between  body-surface  and  age  with  girls 68 

15.  Body-weight,  pulse-rate,  and  basal  heat  production  per  24  hours,  No.  145  . .  114 

16.  Body-weight,  pulse-rate,  and  basal  heat  production  per  24  hours,  Nos.  139 

and  171 124 

17.  Body-weight,  pulse-rate,  and  basal  heat  production  per  24  hours,  Nos.  119, 

122,  127,  and  138 125 

18.  Body-weight,  pulse-rate,  and  basal  heat  production  per  24  hours,  Nos.  113, 

126,  131,  and  142 126 

19.  Body-weight,  pulse-rate,  and  basal  heat  production  per  24  hours,  Nos.  115, 

123,  136,  and  160 127 

20.  Body-weight,  pulse-rate,  and  basal  heat  production  per  24  hours,  Nos.  148, 

161,  172,  and  173 129 

21.  Body-weight,  pulse-rate,  and  basal  heat  production  per  24  hours,  Nos.  153, 

155,  158,  and  166 130 

22.  Basal  heat  production  of  boys  per  24  hours  referred  to  age 133 

23.  Basal  heat  production  of  girls  per  24  hours  referred  to  age 135 

24.  Basal  heat  production  of  boys  per  24  hours  referred  to  age  (earlier  investi- 

gators)     137 

25.  Basal  heat  production  of  girls  per  24  hours  referred  to  age  (earlier  investi- 

gators)     138 

26.  Basal  heat  production  of  boys  per  24  hours  referred  to  body-weight 140 

27.  Basal  heat  production  of  girls  per  24  hours  referred  to  body-weight 142 

28.  Basal  heat  production  of  boys  per  24  hours  referred  to  body-weight  (earlier 

investigators) 143 

29.  Basal  heat  production  of  girls  per  24  hours  referred  to  body-weight  (earlier 

investigators) 144 

30.  Basal  heat  production  of  boys  per  kilogram  of  body-weight  per  24  hours 

referred  to  age 147 

31.  Basal  heat  production  of  girls  per  kilogram  of  body-weight  per  24  hours 

referred  to  age 149 

32.  Basal  heat  production  of  boys  per  kilogram  of  body-weight  per  24  hours 

referred  to  age  (earlier  investigators) ; 150 

33.  Basal  heat  production  of  boys  per  kilogram  of  body-weight  per  24  hours 

referred  to  age  (Sonde"n  and  Tigerstedt,  C.  Tigerstedt,  and  B.  and  T.)  ...   152 

34.  Basal  heat  production  of  girls  per  kilogram  of  body-weight  per  24  hours 

referred  to  age  (Sonde"n  and  Tigerstedt,  and  B.  and  T.) 152 

35.  Basal  heat  production  of  boys  per  kilogram  of  body-weight  per  24  hours 

referred  to  weight 154 

v 


VI  ILLUSTRATIONS. 

PAGE. 

FIG.  36.  Basal  heat  production  of  girls  per  kilogram  of  body-weight  per  24  hours 

referred  to  weight 155 

37.  Basal  heat  production  of  boys  per  kilogram  of  body-weight  per  24  hours 

referred  to  weight  (earlier  investigators) 157 

38.  Basal  heat  production  of  boys  per  24  hours  referred  to  body-surface 161 

39.  Basal  heat  production  of  girls  per  24  hours  referred  to  body-surface 164 

40.  Basal  heat  production  of  boys  per  square  meter  of  body-surface  per  24  hours 

referred  to  surface 165 

41.  Basal  heat  production  of  girls  per  square  meter  of  body-surface  per  24  hours 

referred  to  surface 166 

42.  Basal  heat  production  of  boys  per  square  meter  of  body-surface  per  24  hours 

referred  to  body-weight 167 

43.  Basal  heat  production  of  girls  per  square  meter  of  body-surface  per  24  hours 

referred  to  body-weight 169 

44.  Basal  heat  production  of  boys  per  square  meter  of  body-surface  per  24  hours 

referred  to  body-weight  (earlier  investigators) 171 

45.  Basal  heat  production  of  boys  per  square  meter  of  body-surface  per  24  hours 

referred  to  age 174 

46.  Basal  heat  production  of  boys  per  square  meter  of  body-surface  per  24  hours 

referred  to  age  (earlier  investigators) 175 

47.  Basal  heat  production  of  girls  per  square  meter  of  body-surface  per  24  hours 

referred  to  age 175 

48.  Comparison  of  basal  heat  production  of  children  and  adults  per  24  hours 

referred  to  body-weight .  .  .  .  * 179 

49.  Comparison  of  basal  heat  production  of  children  and  adults  per  24  hours 

referred  to  body-surface 180 

50.  Comparison  of  basal  heat  production  of  children  and  adults  per  kilogram 

of  body-weight  per  24  hours  referred  to  weight 181 

51.  Comparison  of  basal  heat  production  of  children  and  adults  per  square  meter 

of  body-surface  per  24  hours  referred  to  weight 181 

52.  Basal  heat  production  of  men  per  kilogram  of  body-weight  per  24  hours 

referred  to  weight 182 

53.  Basal  heat  production  of  women  per  kilogram  of  body-weight  per  24  hours 

referred  to  weight 182 

54.  Basal  heat  production  of  men  per  square  meter  of  body-surface  per  24  hours 

referred  to  body-weight 183 

55.  Basal  heat  production  of  women  per  square  meter  of  body-surface  per  24 

hours  referred  to  body-weight 183 


METABOLISM  AND  GROWTH  FROM  BIRTH  TO 
PUBERTY. 


INTRODUCTION. 

In  the  past  decade  the  trend  of  thought  in  the  physiology  of  growth 
has  been  towards  a  chemical  analysis  of  the  several  growth  factors. 
The  embryonic  animal  (which  with  mammals  receives  nourishment 
from  its  mother  through  the  placenta,  and  with  other  animals  from 
the  previously  deposited  food  material  in  the  egg)  grows  in  accordance 
with  the  nutrients  supplied.  After  birth  various  types  of  foods  are 
brought  to  it  by  the  mother  or  by  other  agencies.  The  selection  of 
the  diet  best  fitted,  both  in  amount  and  in  quality,  to  acquire  growth 
has  received  a  great  deal  of  experimental  attention.  The  importance 
of  the  mineral  constituents  and  the  nature  of  the  proteins  used  in  the 
construction  of  new  tissue  have  been  emphasized;  particularly,  the 
so-called  " unidentified  food  accessory  substances,"  which  make  for 
growth,  have  been  exhaustively  studied  by  Hopkins,1  Osborne  and 
Mendel,2  and  McCollum.3  As  a  result  of  these  extensive  investigations 
of  the  subject,  it  is  clear  that  a  large  number  of  factors,  heretofore 
almost  neglected  in  research,  are  absolutely  essential  for  the  proper 
growth  of  the  immature  animal. 

With  a  study  of  these  essentials  there  has  proceeded,  although 
perhaps  with  less  intensity,  a  study  of  certain  physiological  constants 
characteristic  of  the  immature  animal,  particularly  of  the  human 
animal.  While  the  anthropologists  have  given  us  extensive  measure- 
ments of  the  growth  in  that  period  of  development  in  which  growth 
is  most  marked,  i.  e.,  in  the  earlier  years  of  life,  relatively  little  is 
known  regarding  the  fundamental  basal  metabolism  during  this  period. 
The  Nutrition  Laboratory,  in  the  belief  that  a  careful  survey  should 
be  made  of  the  metabolism  of  all  mankind  from  birth  to  old  age,  has 
been  occupied  for  nearly  a  decade  in  the  charting  of  this  little-known 
field  of  human  basal  metabolism.  The  writers'  special  province  has 
been  that  of  infants  and  children.  As  an  indication  of  the  extent  and 
thoroughness  of  the  original  program  in  its  several  subdivisions,  we 
may  call  attention  to  our  report  of  a  research  on  the  physiology  of  the 
new-born  infant,  in  which  over  100  new-born  infants  were  studied, 

1  Hopkins,  Journ.  Physiol.,  1912,  44,  p.  425. 

5  Osborne  and  Mendel,  Carnegie  Inst.  Wash.  Pub.  No.  156,  1911. 

3  McCollum,  The  newer  knowledge  of  nutrition.     New  York,  1918. 

1 


2    METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

many  a  few  minutes  after  their  birth,  and  all  during  the  first  week  of 
life.1  An  earlier  report  of  a  study  of  infants  has  also  been  published, 
with  the  primary  object  of  indicating  methods  of  study  and  certain 
physiological  correlations,  particularly  pulse-rate  and  metabolism.2 
At  the  tune  of  this  earlier  report,  the  number  of  normal  individuals 
obtainable  was  relatively  few  and  a  somewhat  large  number  of  atrophic 
infants,  with  a  few  pathological  cases,  were  included  to  show  what 
might  be  expected  for  variation  in  metabolism  in  the  hospital  ward. 
With  the  completion  of  the  study  of  new-born  infants,  the  next  step 
was  the  study  of  the  basal  metabolism  of  children  at  various  ages  from 
one  week  to  puberty.  The  results  of  this  latest  investigation  we  pur- 
pose presenting  in  this  report. 

BASAL  METABOLISM. 

Basal  metabolism  may  be  considered  as  the  sum  total  of  all  the 
vital  activities  of  the  quiet  organism  in  the  post-absorptive  condition, 
i.  e.,  the  minimum  or  maintenance  metabolism  unaffected  by  extrane- 
ous factors.  This  may  be  expressed  in  terms  of  heat  produced  or  of 
gaseous  exchange  incidental  to  heat  production  (carbon-dioxide  pro- 
duction and  oxygen  consumption).  Using  this  basal  metabolism  as  a 
standard,  we  may  then  measure  definitely  the  effect  of  superimposed 
factors. 

In  these  studies  of  the  basal  metabolism  from  birth  to  puberty,  it 
has  been  our  aim  to  determine  the  metabolism  at  the  different  ages 
under  identical  conditions  as  far  as  possible,  so  that  the  results  may 
be  entirely  comparable.  To  obtain  comparable  results  with  indi- 
viduals of  varying  ages,  certain  experimental  conditions  should  exist. 
In  the  first  place,  in  view  of  the  pronounced  influence  of  muscular 
activity  upon  basal  metabolism,  it  is  desirable  that  all  subjects  should 
have  the  same  degree  of  muscular  repose.  An  ideal  condition  would 
be  complete  muscular  repose.  The  difficulty  of  securing  such  repose 
with  young  children  is  obvious,  for  infants  of  one  or  two  years  of  age 
differ  widely  in  muscular  movements  and  temperament  from  an 
adolescent  boy  or  girl.  With  adults  and  older  children  the  muscular 
activity  may  be  voluntarily  so  controlled  that  the  increase  in  meta- 
bolism due  to  activity,  even  in  restless  periods,  will  be  but  15  to  20  per 
cent.  With  crying  children,  with  whom  the  activity  is  involuntary, 
the  increment  was  found  in  our  earlier  studies  to  be  at  times  over  200 
per  cent  and  on  an  average  65  per  cent.3 

Second,  it  may  be  stated  that,  theoretically  at  least,  the  ingestion 
of  any  energy-producing  food-material  increases  the  metabolism  by 

1  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  233,  1915. 

2  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914.     For  a  briefer  report,  see 

Benedict  and  Talbot,  Am.  Journ.  Diseases  of  Children,  1914,  8,  p.  1. 

3  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  233,  1915,  p.  112,  table  17. 


INTRODUCTION.  3 

stimulating  the  cells  to  greater  activity.  This  stimulus  is  greatest 
with  protein  foods  and  least  with  fats.  To  secure  comparable  results, 
therefore,  the  ideal  condition  would  be  to  study  all  subjects  in  the 
post-absorptive  state,  i.  e.,  about  12  hours  after  the  last  meal,  when  the 
influence  of  the  preceding  diet  had  disappeared.  With  such  differ- 
ences in  dietetic  habits,  times  of  eating,  and  stomach  capacity  as 
exist  between  infants  a  year  old  and  children  12  years  old,  the  obtaining 
of  ideally  comparable  conditions  in  this  respect  is  likewise  difficult. 

The  third  factor  to  be  considered  in  determining  the  basal  meta- 
bolism is  that  of  sleep.  While  certain  observations  made  in  a  number 
of  laboratories  imply  that  sleep,  per  se,  is  without  profound  effect 
upon  the  metabolism,  yet  in  the  light  of  our  experience  in  this  labor- 
atory during  the  past  decade  we  are  strongly  inclined  to  think  that 
this  is  an  erroneous  conception.  Furthermore,  the  opportunities  for 
error  in  the  usual  methods  of  determination  of  the  metabolism  during 
deep  sleep  are  great.  When  breathing  appliances,  such  as  moutn- 
piece,  nosepieces,  or  mask,  are  used  in  our  experiments,  the  subjects 
have  been  for  the  most  part  required  to  keep  awake  on  the  general 
ground  that  with  sleep  the  facial  muscles  relax,  especially  those  about 
the  mouth,  and  there  is  danger  of  leakage  of  air  under  these  conditions. 
Practically  the  only  method  of  experimenting  which  gives  dependable 
results  with  a  sleeping  subject  is  the  chamber  method,  i.  e.,  with  the 
subject  asleep  inside  one  of  the  several  forms  of  respiration  chamber. 
That  sleep  is  a  factor  of  great  significance  was  clearly  demonstrated 
in  this  laboratory  with  the  subject  of  a  fasting  experiment.1  Recent 
experiments,  as  yet  unpublished,  show  that  the  metabolism  of  a 
sleeping  subject  differs  appreciably  from  that  of  a  subject  awake, 
even  though  in  both  periods  there  is  the  greatest  degree  of  muscular 
repose. 

A  cursory  examination  of  the  data  presented  in  the  literature  on 
the  metabolism  of  children  shows  a  wide  diversity  of  results.  The 
literature  on  the  metabolism  of  infants,  especially  of  the  new-born, 
has  already  been  reviewed  briefly  in  the  two  publications  giving  the 
results  of  our  earlier  studies.2  While  it  is  unnecessary  to  refer  here 
in  detail  to  the  work  already  cited,  it  seems  desirable,  before  giving 
the  results  of  our  own  observations,  to  supplement  the  previous  review 
of  the  literature  by  a  citation  of  the  observations  made  by  other 
workers  with  older  children. 

1  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  203,  1915,  pp.  343  et  seq. 

2  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914,  pp.  11  to  22,  and  Carnegie 

Inst.  Wash.  Pub.  No.  233,  1915,  pp.  12  to  38. 


PREVIOUS  STUDIES  OF  METABOLISM  OF  CHILDREN. 

In  considering  the  previous  studies  with  children,  one  must  differ- 
entiate sharply  between  measurements  of  metabolism  which  are 
possible  only  with  respiration  apparatus  or  calorimeters  and  the 
computation  of  the  energy  requirement  for  the  day  from  a  statistical 
study  of  the  diets  consumed  by  the  infants  or  children  observed. 
The  researches  on  energy  transformation  of  children  may  be  divided 
into  two  classes:  (1)  those  by  the  indirect  method,  in  which  a  study 
is  made  of  the  respiratory  exchange  by  means  of  some  form  of  respira- 
tion chamber,  and  (2)  those  by  direct  calorimetry,  in  which  the  heat 
output  is  determined  with  a  calorimeter. 

Beginning  with  the  calorimetric  researches  of  Richet,  a  number  of 
French  writers  conducted  researches  on  the  metabolism  of  infants  by 
direct  calorimetry,  several  of  these  observations  being  made  with 
calorimeters  devised  by  d'Arsonval.  These  studies  have  already  been 
summarized  in  one  of  our  earlier  reports,1  but  they  have  little  present- 
day  value,  for  the  investigators  disregarded  the  somewhat  considerable 
withdrawal  of  heat  from  the  body  by  the  vaporization  of  water  and 
gave  no  quantitative  information  regarding  muscular  activity.  Fur- 
thermore, much  of  the  French  work  was  done  with  abnormal  children, 
while  our  report  deals  exclusively  with  the  physiology  of  normal  youth. 

Calorimetric  observations  of  the  basal  metabolism  of  children  have 
also  been  made  by  Du  Bois  and  associates,  which  will  be  cited  in  some 
detail  later.  The  greater  part  of  their  computations  and  the  deduc- 
tions therefrom  are,  however,  based  upon  indirect  calorimetry  rather 
than  upon  direct  calorimetric  measurements.  The  observations  of 
the  basal  metabolism  of  infants  made  by  Howland  with  Lusk's  calori- 
meter,2 an  abstract  of  which  was  given  in  our  earlier  report,  are,  so 
far  as  we  know,  the  only  successful  studies  of  infants  which  have  thus 
far  been  made  by  the  direct  method.  Practically  all  of  the  observa- 
tions cited  in  the  following  pages,  therefore,  are  those  made  by  the 
indirect  method. 

Andral  and  Gavarret,  1843. — The  first  experiments  on  children,  made 
by  Andral  and  Gavarret,3  although  having  mainly  an  historical 
interest,  should  certainly  be  considered  in  any  careful  analysis  of  the 
literature.  Since  at  this  early  date  the  authors  laid  special  stress  upon 

1  Detailed  reference3  to  the  researches  of  these  investigators  are  given  in  Benedict  and  Talbot, 
Carnegie  Inst.  Wash.  Pub.  No.  201,  1914,  pp.  11  to  14. 

» Howland,  Proc.  Soc.  Exp.  Biol.  and  Med.,  1911,  8,  p.  63;  Hoppe-Seyler's  Zeitschr.  f.  Physiol. 
Chem.,  1911,  74,  p.  1;  Trans.  15th  Int.  Congress  on  Hygiene  and  Demography,  Washing- 
ton, 1913,  2,  p.  438.  Cited  by  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201, 
1914,  p.  22. 

3  Andral  and  Gavarret,  Ann.  d.  Chim.  et  d.  Phys.,  1843,  ser.  3,  8,  p.  129. 

4 


PREVIOUS   STUDIES   OF   THE   METABOLISM   OF   CHILDREN.         5 

the  influence  of  puberty,  the  figures  are,  in  the  light  of  modern  studies  at 
this  age,  worthy  of  even  greater  consideration.  Andral  and  Gavarret 
employed  a  copper  mask  attached  to  the  subject's  face  and  collected 
the  expired  air  in  large  glass  globes,  this  air  being  subsequently  ana- 
lyzed. They  report  a  large  series  of  experiments  (8  to  13  minutes 
long)  with  a  great  many  individuals,  some  of  them  children.  The 
experiments  were  all  made  in  the  early  afternoon  and  at  the  same 
interval  after  food,  and  an  attempt  was  made  on  the  part  of  the  experi- 
menters to  have  all  subjects  with  the  same  degree  of  muscular  activity, 
presumably  in  the  sitting  position.  Although  reported  on  the  basis 
of  carbon  per  hour,  their  data  have  been  recalculated  to  the  basis  of 
carbon  dioxide  by  Sonden  and  Tigerstedt1  and  are  presented  in  table  1 
as  given  by  them,  together  with  our  computations  of  the  heat  produc- 
tion per  24  hours. 

TABLE  1. — Metabolism  of  boys  and  girls  (Andral  and  Gavarret). 


Carbon 

Heat 

Carbon 

dioxide 

(computed) 

Subjects. 

Age. 

per 

produced 

per 

Remarks  regarding  muscular  system. 

hour. 

per 

24 

hour.1 

hours.3 

yrs. 

grams 

grams 

cols. 

Boys  .  .  . 

8 

5.0 

218.3 

1,318 

Average. 

10 

6.8 

24.9 

1,793 

Well  developed. 

11 

7.6 

27.9 

2,009 

Do. 

12 

7.4 

27.1 

1,951 

Average. 

12 

8.3 

30.4 

2,189 

Very  well  developed. 

14 

8.2 

30.1 

2,167 

Average. 

15 

8.7 

31.9 

2,297 

Do. 

Girls... 

10 

6.0 

22.0 

1,584 

Well  developed.          1 

11 

6.2 

22.8 

1,642 

Do.                         1  Puberty  not 

13 

6.3 

23.1. 

1,663 

Mediocre.                      |   established. 

16* 

7.1 

26.1 

1,879 

Very  well  developed.  J 

15| 

6.3 

23.1 

1,663 

Average;  puberty  established. 

1  Computed  by  Sonden  and  Tigerstedt,  Skand.  Arch.  f.  Physiol.,  1895,  6,  pp.  54  and  56. 

2  Sonden  and  Tigerstedt  give  16.7  gms.  COz;  this  value  corrected  by  us. 

3  Heat  computed  from  carbon-dioxide  production,  assuming  3  calories  per  gram  of  carbon  dioxide. 

The  authors  conclude  that  with  males  there  is  a  steady  increase  in 
the  carbon-dioxide  production  between  8  and  30  years.  At  the  time 
of  puberty  this  increase  suddenly  becomes  very  large.  Thus,  the 
amount  of  carbon  burned  in  one  hour's  time  increases  progressively 
from  5  grams  in  the  case  of  a  boy  8  years  old  to  8.7  grams  in  the  case 
of  a  boy  15  years  old,  while  with  a  young  man  of  16  years  the  amount 
was  10.2  grams.  With  well-developed  males  from  20  to  28  years  of 
age  the  values  for  carbon  increase  gradually  to  11.2  grams  and  12.4 
grams. 

With  the  females  there  is  likewise  an  increase  in  carbon-dioxide 
production  with  increasing  age,  but  at  the  time  of  puberty  this  increase 


Sonden  and  Tigerstedt,  Skand.  Arch.  f.  Physiol.,  1895,  6,  pp.  54  and  56. 


METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


suddenly  ceases  and  the  amount  of  carbon-dioxide  produced  remains 
stationary,  being  nearly  what  it  was  in  childhood.  Thus,  with  a  girl 
13  years  old  the  carbon  burned  per  hour  was  6.3  grams;  with  a  girl 
15|  years  old,  who  had  not  yet  reached  puberty,  the  value  found  was 
7.1  grams,  while  with  another  girl  of  the  same  age,  who  had  reached 
puberty,  the  value  was  only  6.3  grams. 

Comparing  the  two  sexes,  Andral  and  Gavarret  conclude  that  the 
male  child  burns  more  carbon  than  the  female,  on  the  average  about 
1  gram  more  of  carbon  per  hour. 

The  absence  of  weights  and  heights  in  the  report  lessens  its  value, 
but  in  view  of  the  subsequent  researches  of  Du  Bois  and  certain  data 
accumulated  by  us  these  early  conclusions  with  regard  to  the  influence 
of  puberty  are  of  special  significance. 

Scharling,  1848. — Publishing  simultaneously  with  Andral  and  Gavar- 
ret, Scharling1  reports  experiments  with  a  number  of  subjects,  two  of 
them  children  of  the  age-range  we  are  considering  in  this  report,  one 
a  boy  of  9f  years  of  age  weighing  22  kg.,  and  one  a  girl  of  10  years 
weighing  23  kg.  Scharling's  apparatus  was  a  respiration  chamber,  a 
brief  description  of  which  has  been  given  in  a  previous  report.2  The 
values  of  special  significance  in  connection  with  the  discussion  of 
basal  metabolism  are  those  on  the  boy  and  girl  in  table  2. 

TABLE  2. — Basal  metabolism  of  children  (Scharling). 


Subject. 

Age. 

Body- 
weight. 

Carbon  per 
hour  in 
Danish 
"gran." 

Carbon 
dioxide 
per  hour.1 

Carbon 
dioxide 
per  kg. 
per 
24  hours. 

Heat 
(com- 
puted) 
per 
24  hours.* 

Heat  (com- 
puted) 
per  kg. 
per 
24  hours. 

Boy  
Girl  

yrs. 
9f 

10 

kilos. 
22 

23 

76.2 
74.8 
65.5 
75.1 

grams. 
17.2 
16.9 
15.0 
17.2 

grams. 
18.7 
18.4 
15.7 
17.9 

cats. 
1,238 
1,217 
1,080 
1,238 

cals. 
56.3 
55.3 
47.0 
53.8 

1  In  recalculating  carbon  to  basis  of  carbon  dioxide,  estimated  that  1  Danish  "gran"  (the  measure 

used  by  Scharling)  equals  0.0621  gram. 

2  Heat  computed  from  carbon-dioxide  production,  assuming  3  calories  per  gram  of  carbon  dioxide. 

Forster,  1877. — The  next  recorded  observations  on  children  are  the 
studies  made  by  Forster3  in  Munich  in  1877.  These  are  presented  in  a 
fragmentary  manner  in  somewhat  inaccessible  publications.  Certain 
of  Forster's  results  were  abstracted  in  our  two  previous  publications, 
but  as  his  studies  have  a  special  historical  interest  as  being  the  first 

1  Scharling,  Ann.  d.  Chem.  u.  Pharm.,  1843,  45,  p.  214;   reprinted  in  detail  in  Ann.  d.  Chim   et 

d.  Phys.,.  1843,  ser.  3,  8,  p.  478. 

2  Benedict  and  Carpenter,  Carnegie  Inst.  Wash.  Pub.  No.  261,  1918,  p.  13. 

'Forster,  Amtl.  Ber.  d.  50  Versamml.  deutsch.  Naturf.  u.  Aerzte  in  Miinchen,  1877,  p.  355; 
also  v.  Ziemssen's  Handbuch  der  Hygiene,  Leipsic,  1882,  1,  p.  76.  See  also  Magnus-Levy 
and  Falk,  Archiv  f.  Anat.  u.  Physiol.,  1899,  Suppbd.,  p.  356. 


PREVIOUS   STUDIES   OF   THE   METABOLISM   OF   CHILDREN.         7 

made  by  the  Pettenkofer  and  Voit  method,  and  include  observations 
on  older  children,  it  seems  advisable  to  consider  them  somewhat  more 
extensively  here.  In  his  recognition  of  the  importance  of  a  study  of 
the  metabolism  of  youth,  Forster  was  undoubtedly  stimulated  by  the 
wonderful  observations  of  Pettenkofer  and  Voit.  The  statement  made 
in  our  earlier  publication,1  that  he  used  the  large  Pettenkofer- Voit 
respiration  chamber,  is  obviously  erroneous;  we  have  been  unable  to 
find  a  description  of  the  exact  size  of  chamber  that  he  used.  In 
amplification  of  the  records  of  Forster's  investigations  previously 
reported  by  us,  the  following  data  should  be  given: 

Forster2  states  that  he  studied  a  number  of  children  varying  in  age 
from  14  days  to  13  years,  using  a  Pettenkofer- Voit  respiration  chamber 
and  determining  the  carbon-dioxide  excretion.  The  experiments 
with  nursing  infants,  which  continued  from  3  to  5  hours  each,  were 
made  in  the  intervals  between  the  nursings.  With  the  other  children 
the  experiments  were  made  in  the  morning.  The  supper  given  the 
children  the  night  before  the  experiment  consisted  of  milk  with  a  little 
bread;  from  1|  to  2  hours  before  the  beginning  of  the  experiment, 
they  all  received  100  grams  of  milk  and  a  small  piece  of  bread  (about 
50  grams).  During  the  experiments  the  nursing  infants  slept  the 
greater  part  of  the  time;  the  other  children  remained  very  quiet,  for 
the  most  of  the  time  sitting  and  with  nothing  special  to  do.  In  con- 
formity with  the  usage  of  a  number  of  writers  at  about  that  period, 
Forster  reported  his  results  as  grams  of  carbon-dioxide  excreted  per 
hour  for  each  10  kg.  of  body-weight.  The  results  are  given  in  table  3. 

TABLE  3. — Carbon-dioxide  production  of  children  (Forster) 


Subject. 

Age. 

Carbon-dioxide 
production  per 
10  kg.  per  hour. 

Girl  (nursing  infant)  

14  days  

grams. 
9.0 

Boys  and  girls  

3  to  5  years  

11.7 

Do  

6  to  7  years  

11.7 

Do  

9  to  13  vears  

8.9 

These  values,  which  are  not  far  from  10  to  12  grams  per  hour  for  each 
10  kg.  of  body-weight,  Forster  compares  with  those  obtained  by 
Pettenkofer  and  Voit  for  men  calculated  to  the  same  basis  of  body- 
weight.  The  values  for  adults  are,  for  the  most  part,  one-half  of 
those  found  with  the  children.  Forster  concluded  that,  since  the 
children  during  the  experiment  were  usually  quiet  and  with  approxi- 
mate hunger,  there  is  a  very  much  greater  oxidation  of  nitrogen-free 
material  with  children  than  with  adults  under  the  same  external 

1  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914,  p.  11. 
'Forster,  v.  Ziemssen's  Handbuch  der  Hygiene,  Leipsic,  1882,  1,  p.  76. 


8    METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

conditions.  He  pointed  out  that  this  is  likewise  true  even  during 
sleep,  when  the  metabolism  is  lower,  for  Lewin's  adult  subject1  gave 
off  in  sleep  3.5  grams  of  carbon  dioxide  per  10  kg.  of  body-weight  per 
hour,  while  Forster's  sleeping  infant  gave  off  9  grams  of  carbon  dioxide. 

Speck,  1889. — Speck's  observations  on  children  really  antedated  the 
work  of  Forster,  for,  although  his  results  were  not  published  until 
1889,2  experiments  on  a  13-year-old  girl,  weighing  35  kg., 'were  begun 
on  September  2,  1871,  and  continued  at  intervals  for  two  or  three 
weeks.  Speck  points  out  that  this  child  used  less  oxygen  than  a 
normal  man,  but  when  the  results  were  computed  on  the  basis  of 
oxygen  consumption  per  kilogram  of  body-weight  the  metabolism  of 
the  child  appeared  to  be  more  intensive  than  that  of  the  adult.  All 
the  experiments  with  this  subject  were  made  in  the  standing  position 
and  without  food.  Beginning  September  5,  1877,  six  experiments  in 
about  two  weeks  were  made  with  a  13-year-old  boy,  weighing  38  kg. 
During  these  observations  the  boy  was  without  food  and  sat  reading 
quietly.  Both  the  total  carbon-dioxide  production  and  the  oxygen 
consumption  were  less  than  with  the  average  man,  but  much  higher 
when  computed  on  the  basis  of  body- weight.  Thus  the  total  oxygen 
consumption  was  239  c.  c.  per  minute  and  6.3  c.  c.  per  kilogram  of 
body-weight;  the  respiratory  quotient  was  0.824.  Still  another 
series  of  experiments  was  made  by  Speck  August  22  to  29,  1881,  the 
subject  being  a  10-year-old  girl,  weighing  25.4  kg.  This  girl,  when 
studied  5  hours  after  breakfast  and  while  she  was  sitting  quietly 
reading,  gave  low  values  as  compared  to  those  obtained  with  a  man, 
but  on  the  basis  of  body-weight  the  results  were  much  higher.  The 
average  total  oxygen  consumption  was  172  c.  c.  per  minute  and  6.9  c.  c. 
per  kilogram  of  body-weight  per  minute;  the  respiratory  quotient 
was  0.855.  Since  a  normal  man  gave  about  4  c.  c.  of  oxygen  per 
kilogram  of  body-weight  per  minute,  he  concluded  that  a  small  body 
absorbs  relatively  more  oxygen  than  a  larger  one  and  that  during  the 
years  of  growth  the  oxygen  absorption  is  greater  than  with  adults; 
furthermore,  that  under  like  conditions  males  have  a  greater  metab- 
olism than  females. 

As  Speck's  experiments  were  made  with  the  subject  sitting  (and  in 
one  instance  standing)  instead  of  with  the  subject  lying,  and  in  a 
number  of  instances  with  food  in  the  stomach,  the  results  are  not 
strictly  comparable  with  those  of  modern  work.  It  is,  however,  sig- 
nificant that  Speck's  conclusions,  based  upon  these  physiological 
observations  with  persons  of  various  ages,  and  particularly  with  him- 
self, have  been  unaltered  by  the  results  obtained  by  most  modern 
writers.  His  conclusions  regarding  metabolism  during  youth  are  in 
accord  with  most  subsequent  work. 

iLewin,  Zeitschr.  f.  Biol.,  1881,  17,  p.  71. 

*  Speck,  Physiologic  des  menschlichen  Athmens,  Leipsic,  1892,  p.  iv 


PREVIOUS   STUDIES   OF   THE   METABOLISM   OF   CHILDREN.         9 

Sonden  and  Tigerstedt,  1895. — Concurrently  with  the  description  of 
the  large  respiration  chamber  constructed  in  Stockholm,  Sonden  and 
Tigerstedt  reported  an  extensive  series  of  observations  of  the  resting 
metabolism  of  groups  of  individuals  of  various  ages  inside  the  respira- 
tion chamber.1  The  prime  object  of  their  study  was  to  find  the  carbon- 
dioxide  output  of  groups  of  individuals  for  use  in  determining  the 
needs  of  school-houses  and  other  public  buildings  for  ventilation. 
Accordingly  the  investigators  attempted  to  adjust  the  conditions  of 
their  experiments  to  comply  so  far  as  possible  with  the  demands  of 
the  rooms  and  buildings  under  consideration.  The  subjects  were 
always  in  the  sitting  position,  usually  after  a  breakfast,  and  not 
infrequently  were  eating  small  amounts  of  candy  or  apples.  The 
experimental  conditions  were  therefore  not  ideal  for  measurements 
of  the  basal  metabolism.  It  is  no  adverse  criticism  of  this  wholly 
remarkable  research  to  state  frankly  that  the  results  are  of  no  par- 
ticular value  for  comparison  with  later  experiments  carried  out  with 
the  primary  object  of  measuring  basal  metabolism.  Notwithstanding 
this,  probably  no  one  research  has  contributed  more  to  general  in- 
formation as  to  the  caloric  requirements  of  human  individuals  at 
different  ages  than  has  this  study  of  Sonden  and  Tigerstedt.  The 
apparatus  permitted  the  determination  of  the  carbon-dioxide  con- 
sumption only,  but  the  investigators  were  able  to  compute  the  energy 
requirement  from  this  with  a  considerable  degree  of  accuracy,  espe- 
cially when  the  food  conditions  existing  prior  to  and  during  the  experi- 
ments are  considered. 

The  experiments  were  made  with  subjects  varying  widely  in  age, 
but  our  own  interest  in  the  series  at  this  time  centers  on  the  ages  prior 
to  puberty.  Fortunately  their  research  included  an  extensive  series 
on  children  of  both  sexes,  the  studies  usually  being  made  on  groups  of 
six  subjects.  The  boys  ranged  in  age  from  7  years  and  314  days  to 
14  years  and  199  days,  and  the  girls  from  7  years  and  316  days  to 
14  years  and  15  days.  All  of  the  children  were  taken  from  the  schools 
in  Stockholm  and  remained  reasonably  quiet  during  the  observations, 
sitting  in  chairs  and  reading.  In  most  of  the  experiments  they  ate 
apples  and  occasionally  candy,  but  every  effort  was  made  by  the 
experimenters  to  minimize  the  extraneous  muscular  activity.  The 
results  obtained  with  both  boys  and  girls  are  given  in  table  4,  but  in 
considering  the  data  it  should  be  borne  in  mind  that  they  are  not 
primarily  basal  values.  Sonden  and  Tigerstedt  report  their  results 
as  carbon  dioxide  excreted  per  6  individuals  and  per  half  hour  in 
grams.  In  presenting  the  data  here  we  have  converted  them  to 
calories  per  kilogram  per  24  hours  per  individual,  using  the  respiratory 
quotient  0.90  and  the  calorific  value  of  carbon  dioxide  for  this  respira- 
tory quotient,  i.  e.,  2.785  calories  per  gram  of  carbon  dioxide. 

1  Sonden  and  Tigerstedt,  Skand.  Arch.  f.  Physiol.,  1895,  6,  p.  1. 


10   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

TABLE  4. — Minimum  carbon-dioxide  production  and  heat  production  of  boys  and  girls 
(Sonden  and  Tigerstedt). 


Subjects. 

Average  age. 

Average 
body-weight 
(without  clothing). 

Carbon-dioxide 
production  per  indi- 
vidual per  hour. 

Heat  (computed) 
per  kg. 
per  24  hrs.1 

yrs.    days. 

MM, 

grams. 

cafe. 

Boys  

7      314 

20.1 

20.7 

68.8 

9      217 

27.5 

28.0 

68.1 

10      192 

30.2 

30.7 

67.9 

11       143 

31.6 

30.3 

64.1 

12       173 

34.1 

30.7 

60.2 

13      313 

44.5 

43.0 

64.6 

14       199 

45.3 

39.3 

58.0 

Girls.... 

7       316 

21.8 

22.3 

68.4 

9       334 

26.6 

19.7 

49.5 

11         57 

31.0 

24.0 

51.7 

12        68 

36.2 

25.7 

47.5 

13        53 

39.5 

25.0 

42.3 

14        15 

44.3 

27.0 

40.7 

1  In  computing  heat  assumed  respiratory  quotient  of  0.90. 

Usually  the  observations  continued  for  periods  of  4|  hours.  In 
order  to  approximate  the  minimum  value  for  comparison  purposes,  we 
have  tabulated  only  the  absolute  minimum  found  in  the  results.  This 
was  done  on  the  theory  that  this  minimum  value  represents  the  actual 
minimum  metabolism  during  the  period,  for  otherwise  there  would 
be  an  error  in  the  experimental  technique,  which  is  improbable  in 
view  of  the  usual  accuracy  in  experimentation  of  the  Scandinavian 
investigators.1 

Recognizing  the  importance  of  obtaining  data  as  nearly  as  possible 
during  complete  muscular  repose,  Sonden  and  Tigerstedt  likewise 
made  a  few  experiments  with  individuals  who  slept  inside  the  respira- 
tion chamber,  these  including  two  experiments  with  boys.  The  first 
was  made  with  a  boy  11  years  and  2  months  old,  weighing  without 
clothing  32  kg.  The  experiment  began  at  6  p.m.  The  subject  ate 
supper  inside  the  chamber  at  8h  15m  p.m.,  took  milk  at  10h  30m  p.m., 
and  then  went  immediately  to  bed.  The  carbon-dioxide  excretion 
was  determined  in  2-hour  periods  throughout  the  night.  The  mini- 
mum values  were  found  between  2  and  6  a.m.,  the  values  for  the  two 
periods  being  41  and  37  grams,  respectively.  The  latter  figure  was 
the  absolute  minimum  value  for  the  carbon-dioxide  production  per 
2  hours.  The  second  experiment  was  made  with  a  boy  12  years  of 
age,  weighing  without  clothing  38.3  kg.  The  experimental  conditions 
were  almost  identical  with  those  of  the  first  experiment;  his  last  meal 
prior  to  the  experiment  was  at  4  p.m.  He  went  to  bed  at  10  p.m. 
The  minimum  carbon-dioxide  production  was  found  at  2  a.m.,  i.  e., 
40  grams  per  2  hours.  The  carbon-dioxide  excretion  in  the  period 


For  the  one  apparent  pronounced  exception  to  the  usual  extraordinary  accuracy  of  the  Sond6n 
and  Tigerstedt  technique,  see  critique  of  von  Willebrand's  work,  page  14  of  this  monograph. 


PREVIOUS   STUDIES   OF   THE   METABOLISM   OF   CHILDREN.       11 


just  preceding  the  minimum  period  was  41  grams  and  that  in  the  period 
following  was  42  grams.  For  computing  the  caloric  output  during  this 
time,  we  are  justified  in  using  the  respiratory  quotient  of  0.90  for  the 
first  experiment  and  probably  0.87  for  the  second  experiment.  On  this 
basis  the  minimum  caloric  requirements  for  these  two  boys  would  be 
as  given  in  table  5.  These  values  may  more  properly  be  used  for 

TABLE  5. — Minimum  metabolism  of  boys  during  sleep  (Sonden  and  Tigerstedt). 


Age, 
11  years 
2  months. 

Age, 
12 
years. 

Remarks. 

Body-weight,   without   clothing, 
kilos. 
Carbon-dioxide    production    per 
hour  grams. 
Heat,  computed,  per  24  hours, 
cals. 

32.05 
18.5 
1,237 

38.30 
20.0 
1,373 

In  computing  heat,  assumed 
a  respiratory  quotient  of  0.90 
for  the  11-year  old  boy  and  of 
0.87  for  the  12-year  old  boy, 
as  the  latter  had  had  some- 
what less  food  before  retiring 
for  the  night. 

purposes  of  comparison  with  our  own  results,  as  they  were  obtained 
with  the  subject  in  the  lying  position,  probably  in  deep  sleep,  which  in 
considerable  part  may  offset  the  influence  of  food.  No  night  experi- 
ments during  sleep  were  made  with  girls. 

Hellstrom,  1900. — Employing  presumably  the  large  Stockholm 
respiration  chamber,  Hellstrom1  studied  the  metabolism  of  a  9-year-old 
child  weighing  23.2  kg.  and  found  that  the  child  had  a  heat  production 
of  63  calories  per  kilogram  per  24  hours  or  1,499  calories  per  square 
meter  per  24  hours.  Since  the  original  place  of  publication  of  Hell- 
strom's  article  has  been  inaccessible  to  us,  we  have  had  to  rely  upon 
scattered  statements  concerning  this  experiment  by  von  Willebrand,2 
by  R.  Tigerstedt,3  and  more  recently  by  C.  Tigerstedt.4  As  we  have 
no  information  at  hand  with  regard  to  the  activity  of  the  child  or  the 
height  and  sex,  the  experiment  is  cited  here  simply  as  a  matter  of 
historical  record. 

Rubner,  1902. — Rubner  published  an  interesting  series  of  observa- 
tions on  two  brothers,  one  fat  and  the  other  thin;  also  a  few  experi- 
ments on  two  other  boys.5  As  at  that  time  the  importance  of  muscular 
rest  in  measurements  of  basal  metabolism  had  not  been  so  greatly 
emphasized  as  at  present,  these  children  were  allowed  entire  freedom 
of  movement  inside  the  respiration  chamber.  The  two  brothers 
remained  in  the  chamber  for  22  out  of  the  24  hours,  the  other  two 
boys  only  4  hours.  As  a  result  of  the  experimental  technique  Rubner 

1  Hellstrom,  Studier  ofver  mjolken  sasom  foda,  Helsingfors,  1900,  p.  132. 

2  von  Willebrand,  Finska  Lakaresallskapets  Handlingar,  1907,  49,  p.  421. 
»R.  Tigerstedt,  Nagel's  Handbuch  d.  Physiol.,  Braunschweig,  1909,  1,  p.  476. 

*  C.  Tigerstedt,  Ueber  die  Nahrungszufuhr  des  Menschen  in  ihrer  Abhangigkeit  von  Alter, 
Geschlecht  und  Beruf,  Helsingfors,  1915,  p.  77;  see  also  Skand.  Arch.  f.  Physiol.,  1916, 
34,  p.  151. 

t  Rubner,  Beitrage  zur  Ernahrung  im  Knabenalter,  Berlin,  1902. 


12   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

doubtless  had  data  for  some  periods  in  which  the  subjects  were  asleep, 
but  these  were  not  published — a  fact  to  be  regretted,  for  although  the 
data  were  contaminated  by  the  fact  that  food  had  been  taken  previ- 
ously, it  is  highly  probable  that  the  compensatory  influence  of  sleep 
would  in  large  part  offset  the  stimulus  due  to  the  food.  Since  these 
results  are  not  available,  we  are  unable  to  use  for  comparison  any  of 
the  data  obtained  by  Rubner  in  this  important  research. 

Rubner  compares  the  values  found  with  these  children  with  those 
reported  by  Sonden  and  Tigerstedt.  In  almost  every  instance  he 
finds  that  the  carbon-dioxide  production  per  square  meter  per  hour 
noted  by  Sonde'n  and  Tigerstedt  was  greater  than  that  found  by 
himself.  Rubner  does  not  believe  these  differences  can  be  entirely 
accounted  for  by  the  restlessness  of  the  subjects,  although  this  must 
play  a  considerable  role.  We  find  ourselves  in  full  accord  with  Rub- 
ner's  severe  criticism  of  the  Sonden  and  Tigerstedt  data,  especially 
as  to  their  use  for  comparison;  we  likewise  believe  that  values  obtained 
on  this  basis  can  not  be  used  for  a  satisfactory  demonstration  of  a 
material  alteration  in  the  basal  metabolism  of  youth  as  compared 
with  that  in  old  age.  It  still  remains  a  fact,  however,  that  practically 
all  of  the  criticisms  raised  by  Rubner  against  the  experiments  of  Sonde'n 
and  Tigerstedt  also  apply  to  Rubner's  own  experiments.  For  instance, 
Rubner  criticizes  the  fact  that  Sonde'n  and  Tigerstedt's  subjects 
received  food,  but  the  process  of  digestion  likewise  had  a  part  in  his 
own  experiments,  although  not  so  great  as  in  those  of  Sonden  and 
Tigerstedt.  He  furthermore  takes  exception  to  the  fact  that  Sonden 
and  Tigerstedt's  subjects  moved  about  in  the  chamber  or  were  restless, 
but  his  subjects  moved  and  indeed  walked  about  in  the  chamber  at 
tunes.  Rubner's  criticisms  make  it  especially  clear  that  only  data 
obtained  in  the  post-absorptive  condition  and  in  complete  muscular 
repose  are  ideally  suitable  for  comparing  the  metabolism  of  individuals 
of  different  ages.  These  conditions  were  not  secured  by  either  Sonden 
and  Tigerstedt  or  by  Rubner,  although  the  values  obtained  by  the 
Scandinavian  investigators  with  the  two  boys  studied  throughout  the 
night  approximate  very  closely  the  basal  metabolism,  i.  e.,  very  nearly 
comply  with  basal  conditions  and  prerequisites. 

Since  Rubner  wrote  so  late  as  1902,  it  is  somewhat  surprising  that 
no  mention  was  made  of  the  research  of  Magnus-Levy  and  Falk  pub- 
lished in  1899,  which  met  all  of  the  objections  raised  by  Rubner  to 
the  Sonde'n  and  Tigerstedt  experiments.  These  experiments  of 
Magnus-Levy  and  Falk  were  made,  however,  for  the  most  part  during 
relatively  short  periods,  and  Rubner  strongly  objects  to  respiration 
experiments  made  in  short  periods,  an  objection  with  which  we  can 
not  agree.  Rubner's  chief  conclusion  is  that  the  metabolism  of  nursing 
infants  per  square  meter  of  body-surface  is  no  larger  than  that  of 
adults,  although  he  does  find  an  increased  value  for  young  boys. 


PREVIOUS   STUDIES   OF   THE   METABOLISM   OF   CHILDREN.       13 

This  increase  he  attributes  wholly  to  differences  in  restlessness  and 
activity  and  the  greater  intensity  of  development  of  the  muscular 
system,  an  inherent  restlessness  which  he  thinks  can  not  be  controlled 
with  young  boys.  If  his  results  obtained  during  sleep  had  been 
reported,  much  more  definite  conclusions  could  have  been  drawn. 

Magnus-Levy  and  Folk,  1899. — Magnus-Levy  and  Falk1  presented 
in  1899  the  results  of  the  first  systematic  study  of  the  basal  metab- 
olism of  normal  individuals  from  childhood  to  old  age.  This  research 
was  carried  out  with  all  the  precautions  exacted  by  the  Zuntz  school 
as  to  quietness  and  accuracy  of  technique.  The  mouthpiece  and  the 
Zuntz-Geppert  apparatus  in  general  were  used  for  the  study  of  the 
basal  metabolism  of  11  boys  and  9  girls,  all  14  years  old  or  younger. 

TABLE  6. — Basal  heat  production  of  boys  and  girls  (in  lying  position)  (Magnus-Levy  and  Falk) 


Age, 
years. 

Body- 
weight 
(without 
cloth- 
ing). 

Height. 

Body- 
surface 
(height- 
weight 
chart). 

Heat  (computed) 

Heat  per 
24  hrs.  pre- 
dicted by 
multiple 
prediction 
(adult) 
formula.1 

Com- 
puted 
less 
pre- 
dicted.1 

Per- 
cent- 
age 
differ- 
ence.1 

Per 
24 
hours. 

Per  kilo- 
gram 
per 
24 
hours. 

Per 

square 
meter 
per 
hour. 

Boys. 
21 

6 
6 
7 
7 
9 
10 
11 
14 
14 
14 
Girls. 
6| 

11 
11 
12 
'12 
12 
13 
14 

kilos. 
11.5 
14.5 
18.4 
19.2 
20.8 
21.8 
30.6 
26.5 
36.1 
36.8 
43.0 

18.2 
15.3 
35.0 
42.0 
24.0 
25.2 
40.2 
31.0 
35.5 

cm. 

'iio 

110 
112 
110 
115 
131 
129 
142 
142 
149 

107 
141 
149 
129 
128 
145? 
138 
143 

sq.  m. 

cols. 
782 
926 
970 
1,067 
1,153 
1,036 
1,338 
1,151 
1,310 
1,285 
1,525 

936 
866 
1,313 
1,459 
962 
938 
1,362 
1,217 
1,299 

caZs. 
68.0 
63.9 
52.7 
55.6 
55.4 
47.5 
43.7 
43.4 
36.3 
34.9 
35.5 

51.4 
56.6 
37.5 
34.7 
40.1 
37.2 
33.9 
39.3 
36.6 

cals. 

caZs. 

776 

829 
844 
856 
881 
1,075 
1,002 
1,179 
1,188 
1,309 

cola. 

'  +150 
+141 
+223 
+297 
+155 
+263 
+  149 
+  131 
+  97 
+216 

+19.3 
+17.0 
+26.4 
+34.7 
+  17.6 
+24.6 
+  14.9 
+11.1 
+  8.2 
+16.5 

0.79 
0.83 
1.05 
0.98 
1.20 
1.21 
1.34 

60.8 
52.0 
53.1 
48.9 
45.5 
44.3 
47.4 

46.8 
46.0 
42.6 
41.1 
44.7 
46.1 
45.5 

967 
1,199 
1,281 
1,067 
1,077 

-101 
+  114 
+  178 
-105 
-139 

-10.4 
+  9.5 
+13.9 
-  9.8 
-12.9 

1.17 
1.32 
0.94 
0.95 

1.27 
1.10 
1.19 

1,146 
1,194 

+  71 
+105 

+  6.2 

+  8.8 

1  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  238. 

At  first  thought  it  would  seem  difficult  to  make  metabolism  experi- 
ments with  children,  especially  with  a  child  as  young  as  1\  years, 
with  an  apparatus  using  a  mouthpiece.  Nevertheless  the  results 
show  reasonably  close  agreement  with  each  other.  When  it  is  re- 
membered that  these  investigations  were  carried  out  fully  20  years 
ago,  it  will  be  recognized  that  they  represent  a  remarkable  advance  in 

1  Magnus-Levy  and  Falk,  Archiv  f.  Anat.  u.  Physiol.,  1899,  Suppbd.,  p.  314. 


14   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

the  knowledge  of  the  basal  requirements  of  young  children  over  that 
shown  in  the  earlier  studies.  Singularly  enough,  they  represent 
nearly  the  only  extensive  investigation  in  this  field  for  a  period  of  over 
20  years.  The  results  obtained  by  Magnus-Levy  and  Falk  are  prac- 
tically the  first  data  in  the  earlier  literature  which  are  available  for 
comparison  with  modern  work,  although  the  latter  requires  even  more 
stringent  experimental  conditions,  particularly  as  to  muscular  repose 
and  absence  of  food  in  the  stomach.  A  recent  biometric  analysis1  of 
the  older  subjects  of  Magnus-Levy  and  Falk  shows  that,  on  the  whole, 
these  subjects  apparently  had  a  somewhat  higher  metabolism  than 
that  of  American  subjects.  In  table  6  we  have  abstracted  from  the 
extensive  material  of  Magnus-Levy  and  Falk  the  data  dealing  with 
children  14  years  or  younger,  i.  e.,  the  ages  covered  by  our  own 
observations. 

On  the  assumption  that  the  age  relationship  is  linear,  Harris  and 
Benedict1  point  out  that  the  boys,  particularly  the  young  boys,  are 
characterized  by  measurably  higher  metabolism  than  would  be  com- 
puted from  the  multiple-prediction  methods.  These  differences  are 
by  no  means  so  pronounced  with  the  girls.  Further  discussion  of  this 
point  is  made  on  page  197. 

Von  Wilkbrand,  1907. — Von  Willebrand2  made  a  number  of  experi- 
ments with  boys  9  to  14  years  old.  As  his  results  are  published  in  a 
somewhat  inaccessible  journal,  they  are  given  in  some  detail  in  table  7 
herewith.  The  apparatus  used  were  the  respiration  chamber  in 
Helsingfors  and  the  Pettersson-Sonden  gas-analysis  apparatus.  The 
body-surface  area  was  calculated  by  the  Meeh  formula,  the  constant 
12.165  being  used  for  the  two  youngest  boys  and  12.847  for  the  two 
older.  The  experiments  were  usually  24  hours  long  and  began  in 
the  morning.  All  three  meals  of  the  day  were  taken  in  the  apparatus; 
the  subject  went  to  bed  in  the  evening  about  8  or  9  o'clock  and  rose  in 
the  morning  about  6  o'clock.  In  some  instances  the  subject  slept  for  a 
short  time  during  the  day. 

In  discussing  his  results,  the  author  does  not  use  the  minimum  values 
as  reported  in  our  table,  but  takes  the  average  for  the  whole  24-hour 
period.  He  first  discusses  the  normality  of  his  children  on  the  basis 
of  weight,  age,  etc.,  but  gives  no  heights  for  his  subjects.  As  average 
weights,  he  uses  26  kg.  for  Veikko,  30.5  kg.  for  Viktor,  34.3  kg.  for 
Julius,  and  35.7  kg.  for  Silo.  The  average  carbon-dioxide  production 
per  hour  of  these  subjects  is  given  as  17.9,  21.7,  20.2,  and  18.6  grams, 
respectively.  A  comparison  between  the  carbon-dioxide  production 
of  the  subjects  per  hour  while  awake  with  that  during  sleep  is  given 
hi  table  8.  Von  Willebrand  reports  that  Sond&i  and  Tigerstedt  found 

1  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  233. 
*  von  Willebrand,  Finska  Lakaresallskapets  Handlingar,  1907,  49,  p.  417. 


PREVIOUS   STUDIES   OF   THE   METABOLISM   OF   CHILDREN.       15 

TABLE  7. — Metabolism  of  boys  9  to  14  years  old  (von  WUlebrand). 


Subject,  age,  and  body-weight. 

Carbon 
exhaled  per 
2  hours. 

Time  of  minimum  carbon 
exhaled. 

Carbon-diox- 
ide production 
per  2  hours.1 

Max.' 

Min. 

Max. 

Min. 

grams. 

grams. 

grams. 

grams. 

(    5.37 

9h40mp.m.  to  Ilh40mp.m. 

|" 

(  19.7 

Veikko,    9  years:  25.9  kilos  

14.96 

1    3.25 
\    6.41 

11  40  p.m.          1  40   a.m. 
1  40   a.m.          3  40   a.m. 

I  54.9 

11.9 
1   23.5 

[    7.86 

3  40   a.m.          5  40    a.m. 

J 

(  28.8 

f    6.25 

7  30   p.m.          9  30   p.m. 

} 

f  22.9 

Veikko,    9  years:  26.0  kilos  

11.34 

\     2.75    9  30  p.m.         11  30   p.m. 

41.6 

J    10.1 

1    6.26 

11  30  p.m.          1  30   a.m. 

J 

1  23.0 

{6.05 

9  35   p.m.         11  35   p.m. 

f  22.2 

Veikko     9  years*  25  9  kilos 

18.35 

9.12 
9.37 

11  35  p.m.          1  35   a.m. 
1  35    a.m.          3  35    a.m. 

1  67.3 

I   33.4 
1   34.4 

9.47 

3  35   a.m.          5  35   a.m. 

J 

I  34.7 

f    5.80 

9  30   a.m.        11  30   a.m. 

f  21.3 

Veikko,    9  yeara:  26.0  kilos  

15.13 

!    5.04 
1     6.32 

3  30   p.m.          5  30  p.m. 
9  30  p.m.        11  30  p.m. 

>  55.5 

1 

1    18.5 
|   23.2 

I    7.19 

11  30  p.m.           1  30    a.m. 

J 

I  26.4 

Viktor,  10  years:  30.0  kilos  

16.18 

f    9.34 
1    9.20 

6  15   p.m.          8  15   p.m. 
12  15    a.m.          2  15    a.m. 

|  59.3 

1   34.2 
1  33.7 

{9.71 

11  30   a.m.          1  30   p.m. 

| 

(35.6 

Viktor,  10  years:  30.3  kilos  

16.04 

4.13 
9.48 

5  30   p.m.          7  30  p.m. 
11  30  p.m.          1  30   a.m. 

\  58.8 

15.1 
34.8 

9.68 

1  30   a.m.          3  30   a.m. 

J 

35.5 

Viktor    10  years'  30  8  kilos 

17.12 

1    9.74 
\    9.40 

7  30  p.m.          9  30  p.m. 
9  30  p.m.        11  30  p.m. 

}  62.8 

35.7 
34.5 

f    4.64 

5  30  p.m.          7  30  p.m. 

f  17.0 

Viktor,  10  years:  30.8  kilos  

15.38 

\    7.25 

11  30  p.m.          1  30   a.m. 

\  56.41  \   26.6 

I    6.35 

1  30   a.m.          3  30   a.m. 

j             I  23.3 

Julius,    13  years:  34.1  kilos  

15.28 

I    4.12 
\    5.14 

1  30   a.m.          3  30   a.m. 
3  30   a.m.          5  30   a.m. 

56-°  i  lli 

1    18.0 

Julius     13  years  •  34  4  kilos 

16.51 

j    9.16 

1    9.36 

9  34   a.m.        11  30   a.m. 
5  30   a.m.          7  30   a.m. 

J60.5 

I  3.63 
I  34.3 

Julius,    13  years:  34.4  kilos  

17.60 

1    5.85 
1    6.60 

11  30   a.m.          1  30  p.m. 
1  30  p.m.          3  30  p.m. 

64.5 

21.5 
24.2 

'    8.99 

9  30   p.m.        11  30  p.m. 

33.0 

9.58 

11  30  p.m.          1  30   a.m. 

35.1 

Silo        14  years*  35.6  kilos 

16.18 

5.98 

1  30   a.m.          3  30   a.m. 

59.3 

21.9 

6.22 

3  30   a.m.          5  30   a.m. 

22.8 

10.60 

5  30   a.m.          7  30   a.m. 

38.9 

7.07 

1  00  p.m.          3  00  p.m. 

'  25.9 

9.81 

7  00  p.m.          9  00  p.m. 

36.0 

Silo         14  years-  35  1  kilos 

13.49 

7.39 

9  00  p.m.        11  00  p.m. 

49.5 

27.1 

7.98 

11  00  p.m.          1  00   a.m. 

29.3 

8.14 

1  00   a.m.          3  00   a.m. 

29.8 

f    5.77 

7  00  p.m.          9  00  p.m. 

21.2 

Silo,        14  years:  36.5  kilos  

13.44 

\    5.15 

11  00  p.m.          1  00   a.m. 

49.3 

18.9 

[    5.45 

1  00   a.m.          3  00   a.m. 

20.0 

1  In  9  cases  the  maximum  carbon  exhaled  appeared  in  the  morning  hours;   in  4  cases  in  the 

afternoon;  in  1  case  in  the  evening. 
J  Computed  from  carbon  exhaled,  using  the  factor  11/3. 

the  relation  for  the  carbon-dioxide  production  between  these  two 
conditions  to  be  145  to  100.  With  regard  to  table  8,  which  is  taken 
directly  from  von  Willebrand's1  table,  it  should  be  pointed  out  that 


von  Willebrand,  loc.  cit.,  p.  462. 


16   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

in  computing  the  values  for  asleep  the  author  did  not  select  absolute 
minimum  values,  but  rather  took  an  average  representing  the  entire 
time  the  subject  was  in  bed.  Thus  he  disregards  completely  the 
wholly  impossible  variations  in  the  carbon-dioxide  production  from 
period  to  period. 

TABLE  8. — Comparison  of  carbon-dioxide  production  of  boys  awake  and  asleep  (von  Willebrand). 


Subject. 

Age. 

Body- 
weight. 

Carbon-dioxide 
production  per  hour. 

Relation 
of  awake  to 
asleep. 

Awake. 

Asleep. 

Veikko  

years. 
9 
10 
13 
14 

kilos. 
25.9 
30.8 
34.1 
36.5 

grams. 
24.8 
23.6 
25.8 
21.1 

grams. 
11.7 
15.4 
13.5 
11.1 

212  :  100 
154  :  100 
191  :  100 
190  :  100 

Viktor  
Julius  
Silo  

Average  

23.8 

12.9 

186  :  100 

This  whole  research  is  very  perplexing.  The  differences  in  the 
carbon  dioxide  found  in  the  2-hour  periods  in  different  experiments 
with  the  same  individual,  presumably  when  he  is  asleep,  are  extra- 
ordinary. Such  differences  are  wholly  outside  of  our  experience  in 
the  Nutrition  Laboratory  or  at  Wesley  an  University.  It  appears  as 
though  there  must  be  a  gross  experimental  error,  and  yet  Tigerstedt 
proves  that  the  carbon-dioxide  determinations  in  this  apparatus 
ought  to  be  accurate  to  within  ±0.76  gram  carbon  dioxide.1  If  an 
attempt  were  made  to  use  the  absolute  minimum  figures,  one  would 
find  values  for  the  carbon-dioxide  production  per  2  hours  on  the 
experimental  days  with  Veikko  of  11.9,  10.1,  22.2,  and  18.5  grams; 
with  Viktor,  33.8,  15.2,  34.5,  and  17.0  grams;  with  Julius,  15.1,  33.6, 
and  21.5  grams;  and  with  Silo,  21.9,  25.9,  and  18.9  grams.  These 
low  values  were  not  confined  to  any  one  part  of  the  day,  but  varied 
widely  as  to  the  time  they  appeared. 

Niemann,  1911. — Laying  special  emphasis  upon  the  24-hour  metab- 
olism of  a  bottle-fed  baby,  and  employing  the  small  Pettenkofer- 
Voit  chamber,  Niemann,2  in  Heubner's  clinic,  studied  a  male  child 
designated  as  "normal,"  but  with  a  body-weight  somewhat  low  for  the 
age.  The  child  was  studied  at  the  age  of  3|  months  for  7  days, 
again  at  5  months  for  6  days,  at  8  months  for  6  days,  and  at  9  months 
for  17  days.  Since  the  metabolism  measurements  were  made  for  the 
entire  24  hours,  and  no  subdivision  can  be  made  for  the  periods  when 
asleep,  values  for  basal  metabolism  are  not  obtainable.  As  an  index 
of  the  total  24-hour  caloric  output  of  children,  however,  this  experi- 
ment, along  with  others  of  the  Heubner  clinic  and  from  the  Kaiserin 


1  Tigerstedt,  Skand.  Arch.  f.  Physiol.,  1906,  18,  p.  304. 

2  Niemann,  Jahrb.  f.  Kinderheilk.,  1911,  74,  pp.  22,  237,  and  650. 


PREVIOUS   STUDIES   OF   THE   METABOLISM   OF   CHILDREN.       17 


Auguste  Victoria-Hails,  are  of  special  value, 
reported  in  table  9. 


Niemann's  data  are 


TABLE  9. — Twenty-four  hour  heat  production  of  male  infant  studied  by  Niemann. 


Age. 

Body- 
weight. 

Heat  (computed) 
per  24  hours. 

Remarks. 

Per  kilo.          Per  sq.  m. 

mos. 
^ 
5 
8 

9 

kilos. 
5.12 
5.90 
5.57 
5.98 

cols.                   cats. 
93.0                  1,556 
85.4                  1,500 
88.6                  1,526 
91.2                  1,608 

Computed  by  us,  using  the  Lissauer 
constant  for  surface,  which  we  subse- 
quently show  is  much  more  accurate 
than  that  of  Meeh  (see  p.  60). 

Frank  and  Niemann,  1913. — A  very  much  undernourished  male 
child,  3  months  old,  was  studied  by  Frank  and  Niemann1  in  a  respira- 
tion chamber  after  being  fed  for  6  weeks  on  breast  milk  and  again 
after  4  weeks'  feeding  with  cow's  milk.  The  results  have  no  special 
interest  in  a  study  of  the  normal  respiratory  exchange  of  normal 
children. 

Murlin  and  Hoobler,  1915. — Employing  an  apparatus  essentially 
that  formerly  described  by  us,  Murlin  and  Hoobler2  studied  some 
hospital  cases,  of  which  several  are  considered  by  them  as  perfectly 
normal.3  The  values  computed  for  the  minimum  heat  production 
per  square  meter  per  24  hours,  using  the  more  accurate  Lissauer  method 
of  computing,  are  given  in  table  10.  From  these  cases  and  14  previ- 

TABLE  10. — Minimum  heat  production  of  children  per  24  hours  (Murlin  and  Hoobler). 


Subject. 

Sex. 

Age. 

Body-weight 
(without 
clothing). 

Minimum  heat  production 
(computed)  per  24  hours. 

Per  kilo. 

Per  sq.  m. 
(Lissauer)  . 

A.  S  
W.  L  
E.  H  
E.  N  
M.  M  
C.  M  
W.  S  

M. 
M. 
M. 
M. 
M. 
F. 
M. 

mos. 
2 
2 
2£ 
3 
51 

loj 

11-12 

kilos. 
5.7 
4.4 
4.7 
4.1 
6.5 
9.4 
9.4 

cals. 
50.0 
58.2 
63.0 
61.5 
61.4 
61.8 
60.5 

colt, 

863 
936 
1,035 
960 
1,115 
1,266 
1,239 

ously  published  by  us,  they  discuss  extensively  the  metabolism  in 
relation  to  several  physiological  factors. 

1  Frank  and  Niemann,  Charite-Annalen,  1913,  37,  p.  94. 

2  Murlin  and  Hoobler,  Am.  Journ.  Diseases  of  Children,  1915,  9,  p.  81. 

3  One  of  these  subjects,  E.  N.,  we  would  exclude  from  consideration  because  of  underweight; 

likewise,  we  would  question  considering  M.  M.,  who,  according  to  the  authors,  "no  doubt 
had  an  incipient  tuberculous  infection." 


18   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


Olin,  1915. — In  a  study  made  by  Olin1  under  Professor  Robert 
Tigerstedt  and  published  in  1915,  the  carbon  production  of  boys  from 
9  to  19  years  old  was  determined.  The  children  were  taken  from  an 
elementary  school  in  Helsingfors  and  studied  individually  in  2-hour 
experiments,  usually  in  the  morning  after  a  light  breakfast.  The 
subjects  were  not  allowed  to  move  about  in  the  respiration  chamber, 
but  were  required  to  sit  quiet,  reading.  Although  approximately  200 
children  were  studied,  Olin's  final  discussion  of  the  results  is  based 
upon  the  data  obtained  with  162  subjects.  These  results,  grouped 
according  to  age,  are  given  in  table  11,  which  shows  not  only  the  total 
carbon  production  per  individual,  but  also  the  carbon  production  per 
kilogram  of  body-weight  and  per  square  meter  of  body-surface.  The 
range  in  values  for  the  carbon  production  on  the  basis  of  body-surface 
is  also  included  in  table  11,  and  also  the  percentage  distribution 
according  to  age.  Meeh's  formula  was  employed  in  computing  the 
body-surface,  the  constant  12.205  being  used  for  boys  under  13  years 
and  12.847  for  those  at  and  above  that  age.  It  will  be  seen  that  the 

TABLE  11. — Carbon  production  of  boys  from  9  to  19  years  of  age  (Olin). 


Carbon  exhaled  per  2  hours. 

Average 

Per  square  meter  of  body-surface. 

No. 
of 
sub- 
jects. 

Aver- 
age 
age. 

body- 
weight 
(without 
cloth- 

Body- 
surface 
(Meeh). 

Height. 

Per 

indi- 
vidual. 

Per 
kilo 
of 
body- 

Aver- 

Range. 

Percentage 
distribution. 

Less 

Great- 

ing). 

weight 

age. 

than 

er  than 

8.5 

9.5 

grams. 

grams. 

yrs. 

kilos. 

sq.  TO. 

cm. 

grams. 

grams. 

grams. 

grams. 

p.ct. 

p.ct. 

1 

19 

80.0 

2.385 

177 

18.8 

0.24 

7.90 

7.90           .'...., 

7 

18 

65.6 

2.086 

176 

17.6 

0.27 

8.48 

8.31  to   8.65  1     57 

9 

17 

55.4 

1.864 

170 

16.2 

0.29 

8.66 

8.52        8.80 

33 

22 

18 

16 

59.2 

1.948 

171 

17.6 

0.30 

9.05 

8.89        9.21 

50 

33 

19 

15 

52.9 

1.805 

165 

16.8 

0.31 

9.13 

8.97         9.29 

21 

42 

22 

14 

49.6 

1.726 

160 

15.8 

0.32 

9.13 

8.97        9.29 

41 

36 

26 

13 

43.1 

1.573 

154 

14.4 

0.34 

9.22 

9.08        9.36 

20 

46 

27 

12 

38.1 

1.396 

148 

13.4 

0.36 

9.68    9.56        9.80 

15 

51 

14 

11 

36.1 

1.327 

143 

13.4 

0.37 

10.14 

9.92      10.36 

7 

71 

15 

10 

31.5 

1.217 

140 

11.8 

0.38 

9.79    9.63        9.95 

40 

4 

9 

35.9 

1.299 

139 

11.6 

0.32 

8.60 

carbon  production  per  square  meter  of  body-surface  was  much  larger 
at  11  years  of  age  than  at  any  other  age  studied,  and  increased  regularly 
as  the  age  decreased  from  18  to  11  years.  In  comparing  her  data 
with  those  of  other  investigators,  Olin  states  that,  as  the  experiments 
of  Magnus-Levy  and  Falk  were  made  with  complete  muscular  rest  and 
without  food,  these  subjects  were  more  quiet  than  hers,  who  were  in 

1  Olin,  Finska  Lakaresallskapets  Handlingar,  1915,  57,  p.  1434;  also  Skand.  Archiv.  f.  Physiol., 
1915,  34,  p.  414. 


PREVIOUS   STUDIES   OF   THE   METABOLISM   OF   CHILDREN.       19 

the  sitting  position  rather  than  lying.  She  finds,  also,  that  her  values 
are  much  lower  than  those  of  Sonden  and  Tigerstedt.  She  concludes 
that  the  earlier  statements  that  the  metabolism  is  greater  per  square 
meter  of  body-surface  with  young  individuals  than  with  those  of  full 
growth  are  completely  proved  by  her  results,  which  show  that  the 
metabolism  of  boys  .between  10  and  18  years  of  age  is  distinctly  greater 
per  square  meter  of  body-surface  than  that  of  full-grown  adults.  The 
metabolism  is,  therefore,  not  dependent  solely  upon  the  body-surface, 
but  also  upon  the  age  and  growth. 

Helksen,  1915. — Laying  special  emphasis  upon  the  character  of  the 
diet,  particularly  the  isodynamic  relations  between  carbohydrates  and 
fats,  Hellesen,1  working  in  the  Kaiserin  Auguste  Victoria-Haus  in 
Berlin,  made  two  3-day  experiments  9  days  apart,  hi  March  1911. 
As  is  usual  with  experiments  made  in  that  laboratory,  the  child  was 
studied  for  22  hours  out  of  24  hours  and  carbon  dioxide  and  water- 
vapor  alone  were  measured.  As  is  customary  with  this  type  of  experi- 
ment, the  carbon-dioxide  production  for  special  periods  of  quiet  was 
not  observed.  Hence  no  basal  values  can  be  given,  and  the  data  are 
of  special  interest  only  in  indicating  the  total  24-hour  heat  output  of  a 
child  of  this  age.  From  the  average  of  the  two  experiments,  each  of 
three  days,  it  was  found  that  in  the  first  period  the  child,  a  male, 
weighing  6,684  grams,  had  a  heat  production  per  24  hours  of  454.6 
calories,  per  kilogram  per  24  hours  of  68.0  calories,  and  per  square 
meter  of  body-surface  of  1,245  calories.2  In  the  second  period  the 
weight  was  6,644  grams,  the  heat  per  24  hours  492.4  calories,  per 
kilogram  per  24  hours  74.1  calories,  and  per  square  meter  per  24  hours 
1,353  calories.2 

Du  Bois,  1916. — Subsequent  to  the  classical  study  of  Magnus-Levy 
and  Falk  and  the  data  obtained  in  the  Helsingfors  laboratory,  the 
next  extensive  investigation  of  the  basal  metabolism  of  young  boys 
was  reported  by  Du  Bois.3  Using  the  respiration  calorimeter,  he 
studied  the  carbon-dioxide  output,  oxygen  intake,  and  direct  cal- 
orimetry  of  eight  boys  from  12  years  2  months  to  13  years  11  months. 
For  the  purpose  of  obtaining  further  data  regarding  the  relationship 
between  body-surface  and  metabolism,  the  surface  areas  of  the  sub- 
jects were  measured  by  the  Du  Bois  linear  formula.  So  far  as  the 
number  of  subjects  is  concerned,  the  experimental  plan  was  very 
satisfactory,  but  only  one  experiment  was  made  with  each  subject, 
this  usually  consisting  of  two  successive  1-hour  periods.  Du  Bois's  own 
figures  seem  to  indicate  the  futility  of  this  method  of  experimenta- 
tion, for  they  show  the  following  variations  in  the  heat-production 
per  square  meter  per  hour  for  six  of  the  subjects  studied:  J.D.D.B., 

1  Hellesen,  Nord.  Med.  Arkiv,  1915,  48,  Nos.  14  and  18. 

2  Computed  by  us,  using  the  Lissauer  formula. 

3  Du  Bois,  Arch.  Internal  Med.,  1916,  17,  p.  887. 


20   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

12  per  cent;  Reg.  F.,  15  per  cent;  Harry  B.,  4  per  cent;  Raymond  M., 
7  per  cent;  Henry  K.,  13  per  cent;  and  Leslie  B.,  25  per  cent.     Thus 
out  of  the  eight  boys  whose  values  were  used  for  basal  averages,  four 
show  a  difference  of  12  or  more  per  cent  between  the  results  obtained 
in  the  two  periods.     When  there  is  a  difference  of  but  3  or  4  per  cent, 
an  average  may  legitimately  be  used,  but  with  variations  so  large  as 
these,  it  is  clear  that  one  of  the  two  periods  may  approach  the  basal 
metabolism  and  the  other  must  be  above  it.     Under  these  conditions 
the  averaging  of  the  values  is  questionable  and  tends  to  give  a  high 
value  for  the  basal  metabolism.     Du  Bois  concludes  that  these  boys 
show  on  the  average  a  heat  production  per  unit  of  surface  area  accord- 
ing to  the  Du  Bois  linear  formula  which  is  25  per  cent  higher  than 
the  level  for  adults.     In  analyzing  the  figures,  however,  the  wide 
variations  between  the  results  of  the  two  periods  should  be  borne 
in  mind,  for  values  differing  12  per  cent  or  more  can  hardly  give  a 
satisfactory  base-line.     If  the  lower  of  the  two  values  is  selected  to 
represent  the  base-line,  this  would  reduce  very  perceptibly  the  average 
increase  above  the  adult  level.     It  may  be  questioned,  therefore, 
whether  even  the  lowest  value  represents  the  basal  metabolism,  and  a 
second  experiment  on  each  boy  to  control  these  important  findings 
would  have  been  of  inestimable  value. 

Olmstead,  Barr,  and  Du  Bois,  1918. — Recognizing  the  importance 
of  studying  the  metabolism  of  young  boys  at  about  the  age  of  puberty, 
Du  Bois  and  his  associates1  repeated  the  series  of  experiments  which 
were  made  with  boys  in  1916  to  study  the  changes  in  the  metabolism 
after  two  years  of  growth.  In  this  series  the  wide  variations  between 
the  two  periods  were  eliminated,  the  only  two  subjects  showing  differ- 
ences of  12  per  cent  or  more  being  J.D.D.B.  and  Reg.  F.  The  former 
was  not  included  in  the  calculation  of  the  basal  metabolism;  the  latter 
showed  a  variation  of  17  per  cent.  Since  the  experimental  conditions 
apparently  approached  the  normal,  it  is  probably  legitimate  in  all  cases 
except  Reg.  F.  to  average  the  results  of  the  two  periods,  although  it 
is  still  open  to  question  whether  duplicate  experiments  on  separate 
days  should  not  have  been  made. 

The  authors  note  a  pronounced  decrease  in  metabolism  in  this  second 
series  of  experiments  as  compared  with  the  results  of  the  first  series, 
the  boys  when  two  years  older  showing  a  decrease  in  the  metabolism  of 

13  per  cent.     If  the  minimum  values  obtained  in  the  first  series  of 
experiments  were  used  for  the  basal  metabolism  instead  of  the  average 
of  the  two  periods,  this  decrease  would  obviously  be  less.     All  the 
evidence  seems  to  imply  that  the  conditions  under  which  the  first 
experiments  were  made  were  abnormal  in  that  the  subjects  had  a 
much  more  irregular  metabolism  than  would  normally  be  expected. 

1  Olmstead,  Barr  and  Du  Bois,  Arch.  Internal  Med.,  1918,  21,  p.  621. 


PREVIOUS   STUDIES   OF   THE   METABOLISM   OF   CHILDREN.      21 

The  pulse-rates  in  all  instances  but  one  showed  a  pronounced  decrease 
in  the  second  series  of  experiments,  L.  B.,  for  example,  having  a  pulse- 
rate  of  88  in  the  first  experiment  and  when  two  years  older  a  pulse-rate 
of  65.  It  seems  almost  impossible  to  ascribe  this  decrease  in  metab- 
olism to  a  difference  in  age  of  two  years,  and  this,  combined  with  the 
gross  irregularities  in  metabolism  in  the  two  1-hour  periods  in  the 
first  experiment,  and  pronounced  alterations  in  the  pulse-rates,  makes 
it  all  the  more  desirable  to  have  researches  of  this  type  include  a 
sufficient  number  of  observations  with  each  subject  to  establish 
definitely  the  basal  minimum  metabolism  for  each  individual.  It  is 
clear  that  the  average  values  used  by  Du  Bois  for  the  first  series  of 
experiments  are  certainly  not  basal  values.  From  the  results  of  the 
second  series  of  experiments,  in  which  the  agreement  between  the  two 
periods  is  much  more  satisfactory,  the  authors  consider  that  the  metab- 
olism per  hour  according  to  the  Du  Bois  linear  formula  of  the  boys  is 
still  higher  than  that  of  the  average  adult,  the  difference  being  about 
11  per  cent  for  boys  14  to  15  years  old. 

CONTROL  EXPERIMENTS  AND  BASAL  METABOLISM. 

As  will  be  seen  from  the  foregoing  abstracts  of  previous  investi- 
gations, the  influence  of  both  muscular  activity  and  food  was  dis- 
regarded in  the  earlier  experimental  work  on  metabolism;  conse- 
quently the  values  obtained  in  these  researches  were  usually  not 
strictly  basal.  Most  of  this  material  was  collected  before  the  impor- 
tance of  absolute  muscular  repose  was  sufficiently  recognized  by 
experimenters.  Furthermore,  ocular  observations  of  the  degree  of 
repose  were  used  in  the  earlier  studies,  and  these  are  untrustworthy, 
since  interpretations  vary  widely  and  accurate  records  are  obtained 
only  by  the  graphic  method. 

While  these  faults  in  technique  have,  in  later  days,  been  corrected 
hi  large  part,  greater  uniformity  in  experimental  conditions  and 
standards  should  be  the  rule  in  all  laboratories  studying  metabolism. 
As  emphasized  in  a  previous  section  (see  page  2),  a  knowledge  of  the 
basal  metabolism  is  very  necessary,  since  it  represents  the  basic 
requirements  of  the  human  body  to  which  the  requirements  for  all 
activities  are  added.  According  to  modern  conceptions  of  ideal 
studies  of  the  basal  metabolism,  which  require  the  subject  to  be  in 
the  post-absorptive  condition  (12  hours  without  food)  and  in  com- 
plete muscular  repose,  the  basal  metabolism  is  a  perfectly  definite 
factor.  Even  if  the  values  obtained  are  complicated  by  food,  as  in 
some  of  the  earlier  experiments  in  this  study  of  the  metabolism  of 
children,  yet  the  error  can  not  be  more  than  a  maximum  of  20  per 
cent  for  short  periods  and  rarely  as  high  as  this. 

The  criticism  has  been  raised  that  the  conditions  outlined  for 
obtaining  the  basal  metabolism  are  not  normal  conditions,  but  this 


22   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

is  not  true,  since  all  humans  lie  quietly  in  bed  some  8  or  10  hours 
each  day.  On  the  other  hand,  life  in  a  respiration  chamber  is  not 
normal,  for  the  experimental  periods  of  Sonde'n  and  Tigerstedt,  and 
especially  the  22-hour  periods  of  Rubner,  do  not  represent  normal 
conditions  in  a  child's  daily  existence,  when  he  is  living  a  more  or  less 
active  and  unrestricted  life.  This  may  be  illustrated  by  comparing 
the  daily  requirement  of  Rubner's  boys,  i.  e.,  about  1,700  calories, 
with  the  food  intake  of  the  boys  in  Gephart's  study1  at  St.  Paul's 
School  in  Concord,  New  Hampshire,  which  approximated  5,000 
calories.  An  attempt  to  study  the  requirements  of  the  day  as  a 
whole  by  a  22  to  24  hour  sojourn  in  a  respiration  chamber  would 
therefore  be  a  great  mistake  and  a  return  to  the  standards  of  25  years 
ago. 

The  only  logical  method  for  determining  the  child's  energy  require- 
ments for  a  day's  existence  is  to  obtain,  first,  the  requirement  for 
maintenance  (the  basal  metabolism);  second,  the  additional  energy 
required  for  sitting  in  a  chair  reading  or  studying;  third,  the  energy 
requirement  for  walking;  and  fourth,  that  for  running  and  playing 
or  at  severe  work.  With  adults  we  already  have  much  information  as 
to  the  energy  requirements  for  the  first  three,  and  may  later  be  able  to 
determine  the  enormously  variable  factors  for  the  fourth  requirement. 

In  criticizing  the  experiments  of  Sonde'n  and  Tigerstedt  and  others 
using  a  large  respiration  chamber,  one  should  bear  in  mind  the  fact 
that  they  were  not  planned  to  study  the  so-called  basal  metabolism, 
for  at  that  time  the  conception  of  basal  metabolism  was  but  imper- 
fectly outlined  in  the  minds  of  the  investigators.  Furthermore, 
Sonde'n  and  Tigerstedt  definitely  claim  that  their  results  were  not 
minimum  or  basal.  Except  when  the  data  were  determined  during 
deep  sleep,  the  basal  metabolism  for  these  subjects  was  not  deter- 
mined, for  young  children  as  well  as  adults  were  studied  under  con- 
ditions of  only  comparative  and  not  complete  muscular  repose  and 
during  the  process  of  digestion.  For  a  study  of  the  general  question 
as  to  whether  or  not  there  is  an  alteration  in  the  metabolism  per  unit 
of  weight  or  per  unit  of  surface  with  individuals  of  different  ages,  it 
may  be  that  the  experimental  procedure  used  by  them  would  be 
justifiable,  namely,  a  study  of  all  subjects  under  presumably  like 
(though  certainly  not  basal)  conditions. 

Similarly,  Rubner's  experiments  were  made  to  determine  the  total 
metabolism  during  the  24-hour  period  and  thus  could  not  be  used 
for  basal  comparison.  In  Rubner's  observations  there  was  a  con- 
siderable amount  of  sleep,  which  tended  to  compensate  in  part,  at 
least,  for  the  excess  activity  during  the  waking  hours.  Had  Rubner's 
results  been  so  published  as  to  permit  the  computation  of  the  values 

1  Gephart,  Boston  Med.  and  Surg.  Journ.,  1917'  176,  p.  17. 


PREVIOUS   STUDIES   OF   THE   METABOLISM   OF   CHILDREN.      23 

obtained  with  the  subject  during  sleep,  his  experiments  would  have 
contributed  towards  our  knowledge  of  the  basal  metabolism.  Magnus- 
Levy  and  Talk's  results  approach  more  nearly  the  modern  idea  of 
basal  metabolism,  for  these  experimenters  insisted  upon  repose  and 
upon  absence  of  food. 

While  it  is  assumed  by  Sonde"n  and  Tigerstedt  and  by  other  workers 
that  the  same  degree  of  muscular  activity  can  be  approximated  with 
children  of  different  ages  when  complete  muscular  repose  is  not 
insisted  upon,  this  still  remains  to  be  proved  and  may  fairly  be  ques- 
tioned at  this  tune.  It  is  quite  possible  that  the  relatively  great 
differences  in  the  activity  of  children,  youths,  and  adults  may  account 
for  the  peculiar  findings  recorded  by  these  several  schools  when  an 
attempt  is  made  to  superimpose  a  definite  amount  of  activity  upon 
the  modern  standard  of  complete  repose. 

From  a  purely  scientific  standpoint,  clear-cut  conditions  are  essential 
for  comparative  experiments,  and  if  one  wishes  to  study  the  differences 
hi  metabolism  due  to  differences  in  age  or  sex,  and  particularly  for 
the  various  diseases,  we  must  have  uniform  conditions.  The  basal 
condition  presents  especially  good  opportunities  for  such  uniformity. 
Studies  of  this  kind  are  particularly  advantageous  in  clinical  calor- 
imetry,  for  most  of  the  subjects  observed  would  be  bed-ridden  or 
hospital  patients,  spending  a  considerable  part  of  their  time  under 
conditions  of  muscular  repose. 

The  experiments  of  Sonden  and  Tigerstedt  served  their  special 
immediate  purpose  perfectly,  namely,  to  supply  knowledge  regarding 
the  carbon-dioxide  production  in  school  rooms  and  halls  of  a  group 
of  young  children.  Rubner's  experiments  on  two  boys  served  his 
special  purpose,  but  neither  series  can  be  considered  as  more  than 
studies  of  metabolism  under  special  conditions.  This  likewise  applies 
to  the  major  part  of  the  respiration  calorimeter  experiments  made 
at  Wesleyan  University.  Each  series  demonstrated  its  special  highly 
important  and  fundamental  point,  but  few  of  the  experiments  are 
useful  for  further  comparison.  The  night  experiments  at  Wesleyan 
University  began  at  1  a.  m.  and  were  ended  at  7  a.  m.,  while  the  subjects 
were  still  in  bed,  so  that  results  were  obtained  almost  invariably  for 
six  hours  of  repose.  They  are  therefore  of  more  general  use,  since  the 
subject  was  asleep  and  quiet,  with  the  influence  of  food  at  a  minimum. 

It  is  the  duty  of  twentieth-century  experimenters  to  make  experi- 
ments of  more  than  passing  value.  Each  experiment  should  contribute 
to  our  fundamental  basal  knowledge.  Each  year  sees  an  increase  in 
the  significance  of  normal  values;  an  effort  should  therefore  be  made 
to  secure  normal  values  which  will  be  of  service  not  simply  in  the 
current  year  but  for  a  decade.  There  is  no  excuse  for  present-day 
controls  which  do  not  meet  modern  requirements.  Hundreds  of 
experiments  with  men  and  women  in  this  laboratory  have  shown  that 


24   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

the  post-absorptive  condition  and  muscular  repose  (with  graphic 
registration  by  means  of  a  pneumograph  and  kymograph)  are  readily 
obtained.  Conditions  for  normal  pulse-records  are  thus  ideal  and 
should  accompany  each  experiment.  In  other  words,  normal  experi- 
ments should  serve  not  only  their  immediate  purpose,  but  should 
invariably  contribute  toward  the  sum  of  the  knowledge  of  basal 
metabolism  requirements  of  normal  subjects. 

We  wish  to  enter  a  plea  for  the  same  degree  of  intelligence  in  planning 
normal  control  experiments,  as  is  shown  in  planning  the  original  critical 
experiments  in  every  series  of  metabolism  experiments  conducted  in 
the  future.  If  all  workers  in  metabolism  applied  this  critical  analysis 
to  their  own  work,  the  accumulation  of  basal  material  would  be  very 
rapid,  and  the  work  of  the  several  laboratories  would  be  much  more 
strictly  comparable  than  at  present.  While  it  is  now  practically 
agreed  by  all  laboratories  that  ideal  conditions  are  the  post-absorptive 
state  and  complete  muscular  repose,  the  question  of  sleep  is  at  present 
debatable  ground.  It  is  impossible  to  insure  deep  sleep,  but  it  is 
possible  as  a  rule  to  insure  wakeful  repose. 


HISTORY  AND  PLAN  OF  RESEARCH. 

Aside  from  several  preliminary  observations  at  the  Nutrition 
Laboratory,  in  which  only  the  carbon-dioxide  output  of  infants  was 
determined,  the  first  studies  made  in  this  series  on  the  gaseous  meta- 
bolism of  young  children  were  carried  out  at  the  Massachusetts 
General  Hospital.  A  respiration  laboratory  was  established  in  that 
institution  in  January  1913,  and  observations  by  a  member  of  the 
Nutrition  Laboratory  staff  were  made  almost  daily,  except  during  the 
summer  months,  until  June  1915.  The  infants  first  used  were  mostly 
from  the  Out-Patient  Department,  but  it  soon  became  evident  that 
data  regarding  the  normal  metabolism  of  young  children  could  not  be 
obtained  with  these  infants,  for  normal,  healthy  children  are  not  to 
be  found  in  a  hospital.  These  earlier  observations  therefore  included 
a  considerable  number  of  underweight  children  and  a  few  abnormal 
cases.  The  results  of  the  studies,  which  comprised  data  for  children 
under  two  years  of  age,  have  been  reported  in  detail  in  a  monograph 
and  elsewhere.1  The  later  observations  at  the  Massachusetts  General 
Hospital  were  made  with  new-born  infants  from  the  Boston  Lying-in 
Hospital,  their  age  varying  from  43  minutes  to  8  days.  The  data 
for  105  new-born  infants  have  been  reported  in  a  monograph  and  in 
several  journal  articles.2 

Subsequently  the  apparatus  at  the  Massachusetts  General  Hospital 
was  removed  to  the  Directory  for  Wet-Nurses  of  the  Boston  Infants' 
Hospital,  and  studies  of  children,  varying  in  age  from  two  weeks  to 
two  years,  were  carried  out.  Conditions  here  were  especially  favor- 
able for  the  collection  of  normal  data,  as  the  children,  mostly  breast- 
fed, were  the  offspring  of  resident  normal  wet-nurses,  and  thus  repre- 
sented an  unusually  good  type  of  physical  normality.  Furthermore, 
the  mothers  were  somewhat  under  control.  As  the  inmates  of  this 
institution  constitute  a  more  or  less  floating  population,  a  large  number 
of  babies  were  available  for  observation.  It  was  also  possible  to  follow 
the  life-history  of  a  number  of  the  infants  and  make  observations  of 
their  metabolism  from  time  to  time  over  a  period  of  several  years. 
Some  of  the  children  in  these  prolonged  studies  had  been  previously 
observed  in  the  study  of  new-born  infants.  To  obtain  information 
as  to  the  24-hour  energy  requirement  of  young  children,  two  24-hour 

1  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914.     See,  also,  Benedict  and 

Talbot,  Am.  Journ.  Diseases  of  Children,  1912,  4,  p.  129;  and  1914,  8,  p.  1. 

2  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  233,  1915.     See,  also,  Benedict  and  Talbot, 

Proc.  Nat.  Acad.  Sci.,  1915,  1,  p.  600,  and  Talbot,  Am.  Journ.  Diseases  of  Children,  1917, 
13,  p.  495. 

25 


26   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

experiments  were  carried  out.  The  results  of  these  two  experiments 
have  already  been  briefly  reported.1 

To  complete  the  accumulation  of  data  on  the  normal  metabolism 
of  children  from  birth  to  puberty,  it  was  necessary  to  obtain  older 
children  for  further  studies.  Arrangements  were  therefore  made, 
through  the  courtesy  of  Dr.  Frederic  H.  Knight,  the  superintendent 
of  the  New  England  Home  for  Little  Wanderers,  to  establish  a  respira- 
tion laboratory  in  that  institution.  Studies  were  begun  in  October 
1917  and  continued  until  July  1919.  The  observations  included 
children  of  both  sexes  from  2  to  15  years  of  age. 

The  obtaining  of  successful  experimental  periods  was  very  much  a 
question  of  the  child's  mental  attitude.  To  secure  the  interested  co- 
operation of  the  children  a  system  of  prizes  was  established.  Each 
child  volunteering  as  a  subject  for  an  experiment  received  a  cake  of 
sweet  chocolate  and  a  small  sum  of  money,  varying  from  5  cents  to 
25  cents,  according  to  the  number  of  experimental  periods  possible  to 
be  carried  out  and  the  degree  of  muscular  repose  during  the  experiment. 
In  the  school-room  it  was  made  a  privilege  and  an  honor  for  a  child  to 
act  as  subject  in  these  respiration  experiments;  the  child  reported  at 
the  end  of  an  experiment  to  his  teacher  and  schoolmates  what  prize 
he  had  won,  and  in  this  way  interest  and  enthusiasm  were  maintained 
without  difficulty. 

To  obtain  information  regarding  the  actual  weight  and  height  of 
children  of  school  age,  for  possible  use  hi  establishing  a  normal  stand- 
ard, supplementary  data  were  collected  regarding  the  weight  and 
height  of  the  pupils  of  a  considerable  number  of  private  schools. 

The  results  of  the  observations  made  at  the  Directory  for  Wet- 
Nurses  and  the  New  England  Home  for  Little  Wanderers  have  not 
yet  been  reported  in  detail,2  and  form  the  subject  of  this  monograph. 
This  report  and  the  two  monographs  previously  referred  to  give  a 
complete  summary  of  the  results  obtained  in  the  whole  research  on 
the  metabolism  of  children  from  birth  to  puberty. 

It  will  be  seen  from  the  foregoing  history  of  the  research  on  the 
basal  metabolism  of  children  carried  out  by  the  Nutrition  Laboratory 
during  almost  a  decade  that  the  general  plan  of  study  was  to  make 
observations  on  the  respiratory  exchange  of  a  large  number  of  normal 
children  differing  in  sex,  age,  height,  and  weight.  As  the  observa- 
tions were  made  with  the  children  under  conditions  of  muscular  repose 
and  in  many  instances  with  no  food  in  the  stomach,  the  basal  or 
minimum  metabolism  was  secured.  By  a  comparison  of  the  average 
values  obtained,  the  influence  of  age,  height,  weight,  and  sex  upon 

1  Talbot,  Am.  Journ.  Diseases  of  Children,  1917,  14,  p.  25. 

2  A  preliminary  report  of  the  results  was  given  by  one  of  us  in  the  Shattuck  Lecture  before  the 

Massachusetts  Medical  Society,  June  1919.     See  Benedict,  Boston  Med.  and  Surg.  Journ., 
1919,  181,  p.  107;  also  Talbot,  Am.  Journ.  Diseases  of  Children,  1919,  18,  p.  229. 


HISTORY   AND   PLAN   OF   RESEARCH.  27 

the  heat  production  could  be  found,  normal  standards  derived,  and 
the  basal  energy  requirements  determined.  A  sufficiently  large  num- 
ber of  children  were  studied  to  obtain  reasonably  complete  data  for 
all  ages  between  birth  and  puberty.  In  addition  to  this  general 
method  of  research,  the  problem  of  the  energy  requirements  during 
the  period  of  rapid  growth  in  the  first  years  of  life  was  also  studied 
by  making  observations  on  the  same  individual  at  intervals  over  a  num- 
ber of  years.  In  all,  23  children  were  thus  studied  for  periods  of  a 
few  months  to  three  or  four  years.  The  data  gathered  in  this  research 
thus  provide  information  not  only  as  to  the  energy  requirements  of  a 
large  number  of  children,  but  on  the  energy  requirements  of  the  same 
child  at  varying  ages. 

In  our  earlier  publications1  we  have  already  acknowledged  the  cour- 
tesy extended  to  us  by  the  Trustees  of  the  Massachusetts  General  Hos- 
pital and  the  Boston  Lying-in  Hospital.  We  wish  also  to  acknowledge 
at  this  point  the  courtesy  of  the  Trustees  of  the  Directory  for  Wet- 
Nurses  and  the  Trustees  of  the  New  England  Home  for  Little  Wan- 
derers in  allowing  us  to  carry  on  these  investigations  hi  their  insti- 
tutions. Especially  do  we  appreciate  the  hearty  cooperation  of  the 
superintendent  of  the  latter  institution,  Dr.  Frederic  H.  Knight. 
Many  of  the  observations  were  made  possible  through  the  individual 
interest  of  Miss  Mary  A.  Slade,  a  teacher  at  the  New  England  Home 
for  Little  Wanderers,  who  was  very  successful  in  arousing  the  interest 
of  the  children  in  the  work.  Finally,  too  much  credit  can  not  be 
given  to  the  technical  skill,  devotion,  and  faithfulness  of  Miss  Alice 
Johnson,  Mrs.  Dorothy  A.  Peabody,  and  Miss  Inza  A.  Boles. 

i  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914;    Carnegie  Inst.  Wash.  Pub. 
No.  233,  1915. 


APPARATUS  AND  EXPERIMENTAL  TECHNIQUE. 

The  observations  with  young  children  ranging  in  age  from  a  few 
minutes  after  birth  to  puberty  included  records  of  the  height,  body- 
weight  (nude),  pulse-rate,  body  temperature  (rectal),  muscular 
activity  or  repose,  and  measurements  of  the  gaseous  metabolism. 
From  the  latter,  computations  were  made  of  the  respiratory  quotient. 
A  general  record  was  also  kept  of  the  condition  of  the  child  during 
the  observations,  including  such  data  as  drowsiness,  sleep,  crying,  etc. 
Measurements  were  likewise  made  of  the  body-surface  of  a  consider- 
able number  of  the  children. 

RESPIRATION  APPARATUS. 

The  apparatus  used  for  measuring  the  gaseous  metabolism  in  the 
studies  at  the  Massachusetts  General  Hospital  has  already  been  fully 
described  in  previous  publications.1  In  this  apparatus  a  small  metal 
chamber,  with  a  quickly  removable  cover  made  air-tight  by  a  water- 
seal,  is  connected  with  a  closed-circuit  ventilating  apparatus.  A  rotary 
pump  in  the  ventilating  circuit  draws  the  air  from  the  chamber,  and 
forces  it  through  absorbing  vessels  in  which  are  absorbed  the  water 
and  carbon  dioxide  given  off  by  the  subject.  The  air  is  then  returned 
to  the  chamber  after  pure  oxygen  is  introduced  from  a  cylinder  of  the 
compressed  gas  to  replace  that  used  by  the  child.  A  spirometer  in 
the  ventilating  circuit  provides  for  expansion  in  the  volume  of  air. 
The  amount  of  carbon  dioxide  expired  is  measured  by  weighing  the 
absorbing  vessels;  the  amount  of  oxygen  used  is  determined  by 
metering  the  gas  introduced  into  the  ventilating  circuit.  Inside  the 
metal  chamber  is  a  wire  crib,  with  mattress,  in  which  the  child  lies 
during  the  period  of  observation. 

Since  only  the  basal  or  minimum  metabolism  was  desired  in  these 
studies,  it  was  necessary  to  have  a  record  of  the  degree  of  muscular 
repose  or  activity  of  the  child  to  be  assured  of  comparable  conditions. 
While  ocular  observations  of  the  general  condition  and  activities  of  the 
child  can  be  made  through  the  glass  window  in  the  cover,  such  obser- 
vations give  no  exact  records  to  be  used  as  a  standard  in  comparisons 
of  the  metabolism  measurements.  The  only  method  of  obtaining 
reliable  evidence  of  the  presence  or  absence  of  muscular  movement  is 
by  means  of  graphic  records.  Provision  is  made  for  such  records  in 
this  apparatus  by  suspending  one  end  of  the  wire  crib  by  a  spiral 
spring,  with  a  small  pneumograph  parallel  to  it.  By  this  means  the 

1  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914,  p.  32;  Am.  Journ.  Diseases  of 
Children,  1914,  8,  p.  21. 

28 


APPARATUS  AND  EXPERIMENTAL  TECHNIQUE.       29 

movements  of  the  crib  are  transmitted  through  rubber  tubing  to  a 
tambour  and  small  pointer  outside  the  chamber.  The  adjustment  is 
so  delicate  that  the  slightest  movement  of  the  child  changes  the  center 
of  gravity  and  a  record  is  made  by  the  pointer  on  the  smoked  paper 
of  a  kymograph.  Even  the  movements  of  the  chest- wall  due  to  res- 
piration are  frequently  indicated  on  the  kymograph  record.  A 
straight  line  on  the  kymograph  record  thus  shows  that  the  child  is 
absolutely  quiet. 

The  pulse-rate  is  obtained  with  a  stethoscope  connected  with  the 
observer  outside  the  chamber  by  rubber  tubing.  Records  were 
made  at  intervals  by  the  attendant  nurse  and  show  that  muscular 
activity  instantly  caused  an  increase  in  the  pulse-rate.  Accordingly,  if 
periods  with  a  low  pulse-rate  and  no  activity  are  selected  for  compari- 
son, we  can  be  certain  that  the  values  represent  the  basal  metabolism. 

This  apparatus  was  employed  at  the  Massachusetts  General  Hos- 
pital for  about  two  years  and  was  also  used  for  the  observations  at  the 
Directory  for  Wet-Nurses,  the  only  change  being  that  for  the  older 
children  a  larger  chamber  was  constructed.  The  apparatus  as  used 
in  actual  work  at  the  Directory  for  Wet-Nurses  is  shown  in  figure  1, 
with  assistant  in  charge  and  nurse  recording  the  pulse-rate.  The  end 
of  the  chamber  may  be  seen  at  the  right,  with  the  tambour  and  kymo- 
graph for  recording  the  muscular  activity,  and  connections  with  the 
nurse  who  is  counting  the  pulse-rate.  The  ventilating  system  is  at 
the  left,  with  the  carbon-dioxide  absorbers  and  spirometer  on  the 
upper  shelf  of  the  table,  and  the  water-absorbers  and  blower  on  the 
lower  shelf.  The  gas-meter  for  measuring  the  oxygen  may  be  seen 
in  the  center. 

For  the  experiments  at  the  New  England  Home  for  Little  Wanderers 
a  somewhat  different  form  of  chamber  was  used,  i.  e.,  a  small  clinical 
respiration  chamber,  described  in  detail  by  Benedict  and  Tompkins,1 
and  illustrated  in  figure  2.  This  is  substantially  a  duplicate  of  the 
apparatus  used  for  studying  the  normal  infants,  with  the  exception 
that  the  chamber  is  much  larger  and  hence  of  a  somewhat  different 
type  of  construction.  In  that  used  for  the  infants  the  cover  shuts 
down  like  the  lid  of  a  trunk,  while  in  the  apparatus  employed  for  the 
older  children  the  cover  is  of  a  semi-cylindrical  form  and  is  suspended 
by  two  ropes  connected  with  a  counterpoise,  thus  providing  for  raising 
and  lowering  the  cover.  When  the  cover  is  lowered,  it  enters  a 
narrow  water-seal  which  makes  it  air-tight.  A  rectangular  window 
in  the  cover  provides  for  illumination.  Figure  2  gives  a  general  view 
of  the  respiration  laboratory  at  the  New  England  Home  for  Little 
Wanderers,  with  the  respiration  chamber  at  the  right,  and  the  venti- 
lating and  absorbing  system  at  the  left ;  the  kymograph  and  tambour 
appear  on  a  small  table  in  the  background. 

i  Benedict  and  Tompkins,  Boston  Med.  and  Surg.  Journ.,  1916,  174,  pp.  857,  898,  and  939. 


30   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

EXPERIMENTAL  CONDITIONS. 

Usually  the  length  of  the  observation  was  determined  solely  by  the 
degree  of  repose  of  the  subject.  When  the  pulse-rate  had  fallen  to  a 
normal  level  and  the  kymograph  record  showed  the  child  was  abso- 
lutely quiet,  the  measurements  of  the  metabolism  were  begun.  If  a 
normal  pulse-rate  and  satisfactory  kymograph  record  could  not  be 
obtained,  the  observations  were  discontinued  for  that  day.  The 
measurements  of  the  metabolism  were  divided  into  periods  of  20  or 
30  minutes,  the  number  of  periods  usually  depending  upon  the  con- 
ditions. Since  to  obtain  ideal  conditions  for  measuring  the  basal 
metabolism  there  must  be  no  food  in  the  stomach,  the  measurements 
were  made  in  this  way  whenever  possible. 

With  the  older  children,  voluntary  muscular  control  and  absence  of 
food  in  the  stomach  could  usually  be  secured.  With  young  infants, 
however,  the  ideal  conditions  for  studying  basal  metabolism  could  not 
be  obtained,  particularly  as  to  the  absence  of  food  in  the  stomach. 
In  the  normal  physiological  state,  the  infant  has  more  or  less  food  in 
the  stomach  in  process  of  digestion.  The  infant's  natural  protection 
against  the  lack  of  such  food  is  restlessness,  major  activity,  and  crying. 
In  consequence,  when  we  attempted  to  secure  the  post-absorptive 
condition,  we  were  almost  invariably  confronted  with  the  fact  that  we 
no  longer  had  a  quiet  infant,  that  is,  one  in  muscular  repose.  Of  the 
two  factors  affecting  basal  metabolism — food  and  muscular  activity — 
the  latter  is  so  much  the  greater  that  our  only  alternative  was  to 
allow  a  minimum  amount  of  food  and  thus  secure  muscular  repose. 

This  presence  of  food  in  the  stomach  during  the  observation  con- 
taminates our  comparable  data,  but  was  an  experimental  condition 
which,  for  the  most  part,  it  was  impossible  to  eliminate  with  our 
youngest  subjects.  Schlossmann  and  Murschhauser1  attempted  to 
study  the  metabolism  of  an  infant  during  prolonged  hunger  by  giving 
water  sweetened  with  saccharine  and  salted.  The  influence  of  the 
hunger  was  that  commonly  observed  with  adults,  namely,  a  distinct 
increase  hi  acidosis.  Experiments  with  adults  have  shown  that  acidosis 
stimulates  metabolism,  the  acid  unquestionably  reacting  upon  the 
cells,  stimulating  them  to  greater  activity.  Accordingly,  as  set  forth 
in  an  earlier  publication,2  it  becomes  a  difficult  matter  to  determine 
the  exact  points  at  which  the  post-absorptive  condition  begins  and 
ends  and  hunger  with  stimulating  acidosis  begins. 

While  we  have  in  a  number  of  our  experiments  been  obliged  to  allow 
food  in  the  stomach  during  the  observation,  on  the  other  hand  an 
examination  of  our  data  shows  that  in  most  of  the  observations  with 
the  younger  children  the  subjects  were  asleep.  In  other  words,  at 

1  Schlossmann  and  Murschhauser,  Biochem.  Zeitschr.,  1913,  56,  p.  355. 
1  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914,  p.  147. 


FIG.  1. — Infant  respiration  apparatus  as  used  at  the  Directory  for  Wet-Nurses. 
At  the  right  are  the  respiration  chamber,  the  tambour,  and  kymograph  for  recording  the  muscular 
activity,  also  nurse  counting  pulse-rate.     At  the  left  is  the  absorbing  system,  with  the  carbon- 
dioxide  absorbers  and  spirometer  on  the  upper  shelf  of  the  table,  the  water-absorbers  and 
blower  on  the  lower  shelf.     The  gas-meter  for  measuring  oxygen  may  be  seen  in  center. 


FIG.  2. — Respiration  apparatus  as  used  for  children  at  the  New  England  Home  for 

Little  Wanderers. 

The  respiration  chamber,  with  rounded  cover  and  thermometers,  is  near  the  center  of  the  picture, 
the  absorber  table  at  the  left.  On  the  upper  shelf  of  the  table  may  be  seen  the  carbon- 
dioxide  absorbers  and  the  spirometer;  on  the  lower  shelf  are  the  blower  and  the  water- 
absorbers.  Behind  the  table  are  the  large  oxygen  cylinder  and  gas-meter;  the  tambour 
and  kymograph  stand  on  a  small  table  in  the  rear. 


APPARATUS  AND  EXPERIMENTAL  TECHNIQUE.       31 

the  age  when  it  was  most  necessary  to  introduce  into  the  metabolism 
measurements  the  stimulating  factor  of  a  small  amount  of  food,  we 
have  the  compensatory  depressing  influence  of  sleep.  It  is  probable 
that  these  to  a  certain  extent  neutralize  each  other.  At  present, 
one  may  not  exactly  calculate  the  influence  of  sleep  on  the  various 
children  studied.  Certainly,  the  ingestion  of  food  on  the  one  hand  and 
the  greater  prevalence  of  sleep  on  the  other  tend  towards  a  compensa- 
tion which  makes  the  measurements  of  the  metabolism  of  the  younger 
children  more  nearly  comparable  with  those  made  with  the  older 
subjects,  who  were  in  many  instances  awake. 


DISCUSSION  OF  RESULTS. 

The  experimental  evidence  accumulated  in  connection  with  this 
research  is  especially  complete  with  regard  to  certain  physiological 
measurements,  particularly  pulse-rate  and  total  metabolism,  with 
incidental  observations  with  regard  to  temperature.  In  the  final 
analysis  of  these  figures  the  writers  regret  that  the  question  of  time 
and  expense  made  it  impossible  to  record  simultaneously  with  these 
measurements  other  important  physiological  factors,  such  as  blood 
pressure,  respiration-rate,  alveolar  air,  and  alveolar  carbon  dioxide, 
for  the  physiology  of  youth  needs  most  exhaustive  study  and  each 
series  of  observations  increases  greatly  in  value  by  being  associated 
with  other  physiological  measurements  accurately  determined.  It  is 
necessary,  therefore,  in  this  discussion  to  lay  special  stress  upon  the 
rather  extensive  series  of  anthropometric  measurements  and  the 
measurements  of  pulse-rate,  rectal  temperature,  and  particularly  basal 
metabolism.  If  the  total  energy  metabolism  is  looked  upon  as  the 
pooled  energy  for  the  day,  involving  all  of  the  various  vital  processes 
which  go  to  make  up  the  physical  and  possibly  intellectual  activities 
of  the  day,  it  can  be  seen  that  its  measurement,  even  if  at  the  present 
time  incapable  of  subtle  analysis,  is  of  great  importance.  Indeed, 
with  the  accumulation  of  data  with  regard  to  the  total  energy  metab- 
olism of  human  individuals,  it  is  becoming  increasingly  evident  that 
this  measurement  is  of  great  physiological  if  not  indeed  clinical  im- 
portance. 

While  the  number  of  pathological  factors,  other  than  the  febrile 
condition,  that  have  thus  far  been  noted  to  increase  metabolism  above 
normal  are  relatively  few,  it  is  highly  probable  that  subsequent  studies 
will  show  deviations  from  the  average  normal  metabolism  produced 
by  disease  or  altered  conditions  of  nutrition.  The  lowering  of  the 
normal  basal  metabolism  results  from  a  general  state  of  undernutrition, 
and  hence  it  is  perfectly  consistent  to  say  that  those  subjects  with 
lowered  basal  metabolism  are  distinctly  below  par.  Where  the  health 
of  the  growing  child  is  of  as  great  significance  as  it  is  now  apparently 
becoming,  any  index  of  vitality  is  valuable.  Whatever  restrictions  or 
procedures  for  reducing  metabolism  may  be  justifiable  with  overfed 
adults,  the  consensus  of  opinion  thus  far  points  strongly  towards  the 
necessity  for  a  surplus  of  food  and  a  high  nutritive  plane  for  the  best 
welfare  of  growing  children. 

To  throw  some  light  upon  the  normal  nutritive  plane  and  to  give 
an  indication  as  to  the  general  trend  of  the  normal  basal  metabolism 
from  birth  through  the  period  of  early  childhood  are  the  main  func- 

32 


NORMALITY   OF   CHILDREN   STUDIED.  33 

tions  of  our  report.  While  this  investigation  was  undertaken  pri- 
marily with  the  idea  of  contributing  to  the  abstract  knowledge  of  the 
pure  physiology  of  youth,  it  is  gratifying  to  note  that  these  results,  as  a 
natural  consequence  of  the  increased  interest  in  the  physiology  of 
youth,  have  to-day  a  distinct  practical  value. 

In  the  discussion  of  our  findings  we  shall  consider,  first,  the  normality 
of  our  children  as  shown  by  the  relationships  between  body-weight, 
height,  and  age  and  by  the  anthropometric  measurements  indicating 
growth,  particularly  the  body-surface  area,  with  a  view  to  establishing, 
if  possible,  the  normal,  average,  and  ideal  states  of  nutrition.  We  will 
then  consider  the  ideal  physical  proportions  of  children,  and  fixing 
these  clearly  in  mind,  will  pass  to  a  consideration  of  the  physiological 
functions  with  special  reference  to  pulse-rate,  rectal  temperature,  and 
particularly  the  gaseous  exchange  and  total  energy  metabolism. 

NORMALITY  OF  CHILDREN  STUDIED. 

In  all  of  our  investigations  thus  far  on  the  basal  metabolism  of 
humans  of  both  sexes  and  of  varying  ages,  one  of  the  prerequisites  has 
been  that  the  subjects  be  individuals  "presumably  in  good  health." 
In  this  stage  of  our  study,  representing  the  metabolism  of  children 
from  birth  to  puberty,  it  seems  to  us  particularly  necessary  to  scrutinize 
the  normality  of  the  children  measured.  Throughout  the  entire 
investigation  we  held  firmly  in  mind  the  idea  that  we  were  primarily 
interested  in  physiological  observations  and  should  avoid,  in  so  far  as 
possible,  any  pathological  or  seemingly  pathological  cases.  Conse- 
quently, there  was  more  or  less  of  a  natural  selection,  which  eliminated 
obviously  pathological  cases.  In  the  course  of  our  investigation, 
however,  it  so  happened,  due  either  to  the  scarcity  of  subjects  at  the 
time  or  to  the  special  features  of  an  individual  case,  that  subjects 
not  obviously  pathological  were  studied,  who  on  closer  scrutiny  would 
not  be  considered  strictly  normal.  It  was  necessary  to  decide  arbi- 
trarily, as  we  proceeded,  what  was  and  what  was  not  physiological. 
No  hard  and  fixed  lines  could  necessarily  be  laid  down;  indeed,  such 
lines  do  not  exist.  Ocular  impressions  of  examining  physicians, 
nurses,  and  attendants  were  relied  upon  to  indicate  whether  or  not 
the  subject  was  normal.  In  all  cases,  however,  there  was  a  distinct 
mental  reservation  that  before  final  publication  the  material  would 
be  thoroughly  tested  and  only  such  as  measured  up  to  a  reasonable 
estimate  of  normality  would  be  included  in  the  discussion  on  basal 
metabolism. 

The  dominant  thought  in  our  consideration  of  the  question  of  the 
normality  of  our  children  is  to  determine  what  degree  of  success 
attended  our  efforts  to  eliminate  incipiently  pathological  material 
from  our  subjects  and  so  enable  us  to  state  with  accuracy  that  we  are 


34   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

dealing  with  the  physiology  of  normal  youth.  In  the  first  place,  our 
own  impressions  of  normality  were  substantiated  by  most  careful 
physical  examinations,  in  which  always  one  and  frequently  two  physi- 
cians passed  critical  judgment  as  to  the  normality  of  each  child.  Since 
this  last  analysis,  however,  must  depend  upon  the  personal  judgment 
of  the  examiner,  we  have  thought  it  would  be  highly  desirable  to  check 
up  the  results  of  the  physical  examinations,  so  far  as  possible,  by  com- 
paring the  cases  passed  upon  as  normal  by  the  physicians  with  some 
recognized  standards  which  would  be  completely  free  from  the  personal 
equation.  To  the  uninitiated  the  personal  impression  made  by  a 
child  is  always  of  great  weight  in  estimating  the  state  of  normality, 
and  one  instinctively  says  whether  a  child  appears  well-nourished  or 
undernourished.  But  age,  height,  and  weight,  as  well  as  girths, 
should  be  taken  into  consideration,  and  it  is  clear  that  personal  im- 
pressions may  very  likely  err  in  estimations  of  this  kind,  and  therefore 
should  be  replaced,  as  far  as  possible,  by  accurately  determined 
measurements.  Furthermore,  it  is  clear  that  sexual  differences  appear 
at  an  early  age,  so  that  boys  and  girls  may  not  be  classed  together. 

At  the  completion  of  our  experimental  details,  therefore,  the  selection 
of  normal  material  presented  a  great  deal  of  difficulty.  We  were 
instantly  confronted  with  the  question  "What  is  normal?"  While 
we  firmly  believe  that  all  obviously  abnormal  children  were  excluded, 
it  still  remains  an  important  point  whether  the  general  run  of  our 
children  measure  up  to  the  idea  of  normality  held  by  many  writers. 
Heretofore  the  conception  of  normality  has  been  in  large  part  based 
upon  the  average,  and  consequently  the  averages  selected  from  a  large 
number  of  measurements  of  children  of  varying  ages,  weights,  and 
heights  have  been  used  to  indicate  the  average  or  normal  growth  for 
age,  height,  or  weight  of  the  child.  This  is  not  the  place  to  define 
what  is  normal  and  what  is  average,  but  this  point  will  be  taken  up 
in  detail  later  on  in  this  discussion. 

STANDARDS  FOR  DETERMINING  THE  NORMALITY  OF  CHILDREN. 

In  considering  the  normality  of  children,  special  emphasis  has 
always  been  laid  upon  the  relationship  between  body-weight  and  age 
or  between  height  and  age,  and  only  relatively  recently  between  height 
and  body-weight,  irrespective  of  age.  The  age  factor  has  always  been 
the  most  important  and  the  ratios  of  height  to  given  age  and  body- 
weight  to  given  age  still  remain  the  most  commonly  used  criteria. 
At  first  sight  this  method  of  comparison  would  appear  to  be  a  relatively 
satisfactory  one.  The  measurements  of  body-weight  and  of  height 
are  apparently  very  simple,  and  yet  both  are  subject  to  considerable 
errors,  particularly  in  the  case  of  boys. 

Weight  of  clothing. — For  many  obvious  reasons,  the  weight  of 
children  above  5  years  of  age  is  almost  invariably  given  with  clothing. 


NORMALITY   OF   CHILDREN   STUDIED.  35 

Not  infrequently  the  weights  of  children  of  all  ages  are  given  with 
clothing  by  various  writers  and  an  attempt  is  made  (a  very  crude 
attempt)  to  correct  for  the  clothing  at  the  time  of  weighing.  This 
method  is  inaccurate,  since  the  weight  of  clothing  varies  with  sex, 
with  the  seasons  of  the  year,  and  with  the  social  position  of  the  child. 
Anyone  can  convince  himself  of  the  probable  errors  involved  simply 
by  emptying  the  pockets  of  a  small  boy.  Scientifically  accurate 
figures  can  therefore  be  obtained  only  when  the  subject  is  weighed 
naked. 

Bowditch,1  Schmid-Monnard,2  Vierordt,3  Griffith,4  and  other  in- 
vestigators have  at  various  times  reported  the  results  of  their  studies 
of  the  weight  of  clothing  worn  by  their  subjects.  In  the  measurements 
of  our  children  we  took  the  opportunity  of  studying  to  some  extent 
the  weight  of  clothing  worn.  Since,  however,  many  of  our  children 
came  from  an  institution  where  the  clothing  was  more  or  less  of  uni- 
form style  and  amount,  our  estimates  of  weight  of  clothing  are  not  of 
sufficient  value  to  record,  for  they  may  have  only  a  local  significance, 
a  fault  in  common  with  many  other  series. 

Another  difficulty  in  using  these  two  measurements  of  body-weight 
and  height  as  standards  for  determining  the  normality  of  children  is 
that  usually  they  are  taken  on  relatively  few  subjects,  and  for  the 
establishment  of  an  average  or  a  normal  value  very  considerable 
numbers  of  measurements  of  both  height  and  body-weight  at  varying 
ages  are  essential.  Height  can  and  should  be  obtained  on  an  indefinite 
number  of  subjects,  weight  also  on  a  large  number,  although  to  be  of 
value  the  weights  should  be  nude  weights.  Unusual  significance  has 
been  recently  attached  to  the  so-called  "stem  length,"  i.  e.,  sitting 
height.5 

For  greater  accuracy,  consideration  should  also  be  given  to  the 
amount  of  food  eaten  and  the  amoimt  of  water  taken;  the  quantity 
of  urine  and  feces  unvoided  are  likewise  of  not  inconsiderable  im- 
portance. It  is  the  present  custom  in  physiological  laboratories, 
where  extreme  accuracy  is  desired,  to  make  sure,  so  far  as  possible, 
that  food  has  not  been  taken  into  the  stomach  for  several  hours 
(usually  12)  before  the  weight  is  measured,  and  that  the  bladder  is 
emptied  immediately  before  weighing  and  feces  passed,  if  possible. 
It  is  obvious  that  these  last  refinements  are  with  difficulty  applicable 
to  the  measurement  of  a  series  of  children.  In  our  own  investigations 
they  were  followed  out  in  as  many  cases  as  possible. 

1  Bowditch,  Eighth  Annual  Report  Mass.  State  Board  Health,  1877,  p.  275. 

2  Schmid-Monnard,  Jahrb.  f.  Kinderheilk.,  1901,  53,  p.  50. 

3  Vierordt,  Daten  und  Tabellen  fur  Mediziner,  Jena,  1906,  3  Aufl.,  pp.  23-24. 

4  Griffith,  N.  Y.  Med.  Journ.,  1917,  106,  p.  823. 

6  Walker,  Proc.  Roy.  Soc.,  B,  1915,  89,  p.  157;  Dreyer,  Lancet,  Aug.  9,  1919;  and  von  Pirquet, 
System  der  Ernahrung,  Berlin,  1917,  p.  48. 


36       METABOLISM   AND   GROWTH   FROM   BIRTH   TO   PUBERTY. 

EARLIER  DATA  SELECTED  FOR  COMPARISON  WITH  OUR  DATA. 

Employing  the  commonly  accepted  standards  for  normality,  i.  e., 
the  relationships  between  body-weight  and  age  and  between  height 
and  age,  we  have  prepared  four  charts  (figs.  3,  4,  5,  and  6),  on  which 
we  have  placed  several  curves,  comparing  our  measurements  of 
weight  and  height  referred  to  age  for  our  laboratory  children1  with 
similar  measurements  derived  from  other  sources.  In  selecting  data 
from  other  sources  for  comparison  we  were  influenced  by  the  considera- 
tions outlined  above  relative  to  accuracy  of  measurements  and  number 
of  subjects  measured.  Almost  at  the  very  outset  it  was  clear  to  us, 
as  has  been  pointed  out  by  Holt,2  that  the  difference  in  normal  may 
to  a  great  extent  be  one  of  racial  characteristics  and  therefore  that 
little,  if  any,  consideration  should  be  given  to  the  average  values  of 
foreign  writers,  especially  when  these  values  deal  with  a  very  homo- 
geneous population.  For  a  working  basis,  however,  for  this  com- 
parison, we  have  chosen,  first,  as  representing  foreign  children,  the 
values  from  two  typical  foreign  investigators,  i.  e.,  those  of  Quetelet3 
and  Schmid-Monnard.4  Fortunately  the  fundamental  and  classical 
investigations  of  Bowditch5  and  the  more  recent  studies  made  in  an 
effort  to  implant  in  the  American  mind  the  importance  of  conserving 
our  youth  have  led  to  the  accumulation  of  a  considerable  amount  of 
data  which  may  be  stated  to  be  fairly  representative  of  the  American 
people.  The  more  recent  data,  particularly  that  of  Crum6  and  Wood,7 
have  been  admirably  collected  by  Gray8  and  have  been  chosen  by  us 
as  best  representative  of  American  children.  Finally,  we  have  also 
made  use  of  measurements  secured  on  private-school  children  by  Holt9 
in  New  York  City  and  by  ourselves  in  private  schools  in  the  vicinity 
of  Boston  and  in  eastern  Massachusetts. 

The  curves  for  all  but  our  laboratory  children  and  those  of  Holt 
were  plotted  from  average  values  representing  definite  age-groups. 
Thus,  the  weights  and  heights  from  Quetelet,  Schmid-Monnard,  and 
Wood,  as  well  as  those  of  our  private-school  children,  were  averaged 
for  each  year,  and  those  from  Crum  for  each  6  months.  The  curves 

1  We  use  the  term  "laboratory  children"  to  indicate  those  children  whose  metabolism  was  directly 

studied  by  us  in  one  or  more  of  the  several  respiration  apparatus,  and  to  distinguish  them 

from  our  group  of  private-school  children. 
*Holt,  Am.  Journ.  Diseases  Children,  1918,  16,  p.  359. 
»  Quetelet,  Anthropometrie,  Paris,  1871,  pp.  177  and  346;  also  Sur  1'homme  et  le  deVeloppement 

de  ses  facult&s,  Paris,  1835,  2,  p.  46. 

4  Schmid-Monnard,  Correspondenzbl.  d.  deutsch.  Gesellsch.  f.  Anthropol.,  1900,  31,  p.  130. 
6  Bowditch,  Growth  of  children,  Public  Document,  Mass.  State  Board  Health,  1877.     Cited 

by  Holt,  Am.  Journ.  Diseases  Children,  1918,  16,  p.  362. 

6  Crum,  Quarterly  Pub.  Am.  Statistical  Assn.,  Sept.  1916,  n.  s.,  No.  115,  vol.  xv,  Boston,  pp. 

332—336. 

7  Wood,  pjersonal  communication  to  Gray. 

8  Gray  and  Gray,  Boston  Med.  Surg.  Journ.,  1917,  177,  p.  894. 

9  Holt,  Am.  Journ.  Diseases  Children,  1918,  16,  p.  359. 


NORMALITY   OF   CHILDREN   STUDIED.  37 

representing  Holt's  data  and  our  own  laboratory  data1  were  obtained 
by  first  plotting  all  the  numerous  measurements  and  then  drawing 
through  the  plotted  points  smoothed  curves  representing  the  general 
trend.  In  each  case  these  smoothed  curves  are  really  composite 
curves  representing  the  judgments  of  five  members  of  the  laboratory 
staff,  who  were  asked  to  sketch  in  on  tracing  paper  their  visualization 
of  the  general  trend. 

While  no  difficulty  was  experienced  in  securing  sufficient  data  with 
regard  to  foreign  children  from  the  classical  researches  of  Vierordt  and 
others,  special  consideration  must  be  given  the  measurements  of 
American  children.  One  of  the  greatest  difficulties  in  this  connection 
is  the  fact  that  most  of  the  body-weight  measurements  of  American 
children,  especially  those  above  5  years  of  age,  include  weight  of 
clothing,  and  this  necessitates  a  rather  uncertain  correction  for  clothing. 
In  the  data  which  we  have  selected,  however,  all  measurements  of 
body-weight,  and  indeed  height,  were  taken  without  clothing,  with 
one  exception.  Quetelet's  measurements  of  weight  involved  weight 
of  clothing,  but  fortunately  he  corrected  his  values  for  the  weight  of 
clothing  worn  by  deducting  one-eighteenth  of  the  total  weight  for 
males  and  one  twenty-fourth  for  females.  Consequently  we  feel 
justified  in  using  his  values  for  comparison  with  our  other  data. 

Of  special  significance  is  our  recalculation,  averaging,  and  charting 
of  a  series  of  figures  compiled  from  the  article  by  Gray,2  who  has  very 
carefully  made  most  suitable  selections  and  who  cites  only  body- 
weights  without  clothing.  For  children  from  6  months  to  4  years  of 
age  Gray  gives  values  from  Crum3  which  are  based  upon  5,602  boys 
and  4,821  girls.  For  children  from  5  years  to  20  years  of  age  he  gives 
values  received  by  him  in  a  personal  communication  from  Professor 
Wood,  of  the  Life  Extension  Institute.4  In  reporting  Crum's  figures, 
Gray  quotes  him  as  inclined  to  think  that  the  children  measured  by 
him  may  be  regarded  "as  somewhat  super-normal,  or  above  average," 
since  they  were  measured  in  connection  with  a  "better  baby  contest," 
a  movement  prompted  by  the  committee  on  public  health  and  instruc- 
tion of  the  American  Medical  Association.  The  great  majority  of  the 

1  The  data  for  the  ages,  weights,  and  heights  of  our  laboratory  children  are  given  in  tables  26, 

27,  and  28  (pp.  112,  116,  and  120)  in  our  subsequent  discussion  of  basal  metabolism.  Addi- 
tional data  for  8  boys  and  4  girls,  for  whom  basal  metabolism  measurements  are  not  avail- 
able but  for  whom  we  have  these  physical  measurements,  are  reported  in  tables  12  and  13 
(pp.  54  and  58)  in  the  discussion  of  anthropometric  measurements.  As  will  be  explained 
in  detail  later,  all  the  individual  measurements  secured  by  us  for  weight,  height,  and  age 
were  not  used  in  plotting  these  charts,  but  the  values  were  averaged  to  a  certain  extent. 
Thus,  a  child  was  considered  a  new  individual  with  an  increase  in  age  of  6  months,  or  with 
an  increase  in  weight  of  1  kg.  up  to  10  kg.  and  of  10  per  cent  beyond  10  kg.,  and  measure- 
ments obtained  on  a  child  on  two  or  three  successive  days  or  on  days  relatively  close  together 
were  often  averaged  as  one  value  rather  than  being  used  separately. 

2  Gray  and  Gray,  Boston  Med.  Surg.  Journ.,  1917,  177,  p.  894. 

3  Crum,  Quarterly  Pub.  Am.  Statistical  Assn.,  Sept.,  1916,  n.  s.,  No.  115,  vol.  xv,  Boston,  pp. 

332-336.     See  also  Gray  and  Gray,  loc.  cit.,  p.  895,  table  2. 

4  Gray  and  Gray,  loc.  cit.,  p.  896,  tables  3  and  4. 


341683 


38       METABOLISM   AND    GROWTH   FROM   BIRTH   TO   PltBERTY. 

children  were  of  American-born  parents,  but  were  of  different  stocks, 
including  German,  Irish,  Swedish,  and  some  Italian.  According  to 
Crum's  statement,  the  measurements  were  made  upon  "  normal  healthy 
children  in  various  sections  of  the  country"1  and  " should  serve  as  a 
fair  guide  for  many  practical  purposes  without  any  additional  refine- 
ments."1 Professor  Wood's  measurements  were  made  on  several 
thousand  boys  and  girls  in  the  Horace  Mann  School,  connected  with 
Columbia  University.  The  heights  and  weights  were  taken  without 
clothing,  but  he  adds  the  important  information  that  the  "weight  of 
clothing  ranges  from  about  3  pounds  in  five-year-old  children  to  6  or  7 
pounds  in  older  pupils,  and  is  slightly  greater  for  boys'  than  girls' 
clothing."2  •  He  considers  that  these  measurements  are  fairly  repre- 
sentative of  healthy  children  in  the  United  States. 

In  quoting  from  Professor  Wood,  Gray  very  properly  brings  out 
that  "a  child  who  is  short  in  stature  for  his  age  is  apt  to  be  under 
weight"2  and  that  children  of  constant  age  but  varying  height  should 
have  different  weights ;  but  for  our  purpose  we  have  taken  the  average 
value  of  all  the  weights  and  all  the  heights  at  the  several  ages,  as 
reported  by  Crum  and  Wood,  and  have  included  them  in  a  combined 
curve  on  our  charts.  It  is  of  considerable  interest  to  note  in  the 
several  charts  that  there  is  no  striking  break  in  the  curve  between 
4  years  of  age,  where  Crum's  data  end,  and  5  years  of  age,  where 
Wood's  begin,  but  that  the  curve  is  reasonably  regular  in  character. 
To  indicate  the  lack  of  data  between  4  and  5  years  of  age  this  portion 
of  the  curve  has  been  drawn  in  as  a  broken  line. 

Holt's  measurements  were  obtained  on  boys  only,  in  the  Browning 
School  in  New  York  City,  a  school  which  in  his  opinion  represents 
one  of  the  better  grades  of  day  schools  in  that  city.  In  all,  1,774 
observations  were  made  "on  about  350  different  boys  whose  weights 
were  taken  semi-annually,  without  clothes,  over  a  period  of  years, 
the  average  number  of  observations  on  each  boy  being  five.  This 
group  of  American  boys,  with  but  few  exceptions,  came  from  wealthy 
families  and  had  had  the  advantage  of  good  care  and  proper  food  all 
their  lives."3 

Our  own  data  for  private-school  children  represent  boys  and  girls 
probably  of  the  same  social  class  as  those  measured  by  Holt.  Records 
of  age,  height,  and  nude  weights  were  made  on  886  boys  from  eight 
private  schools  and  on  323  girls  in  two  private  schools,  in  the  neighbor- 
hood of  Boston  and  eastern  Massachusetts.  Private  schools  were 
selected  because  the  children  attending  them  were  presumably  living 
in  the  most  ideal  home  and  school  surroundings  and  should  be  closer 
to  the  ideal  American  in  physical  development  than  those  living  in 
less  favorable  surroundings. 

1  Gray  and  Gray,  Boston  Med.  Surg.  Journ.,  1917,  177,  p.  895. 

2  Gray  and  Gray,  loc.  cit. ,  p.  897. 

3  Holt,  Am.  Journ.  Diseases  Children,  1918,  16,  pp.  360  and  362. 


NORMALITY   OF   CHILDREN   STUDIED.  39 

Our  laboratory  children,  whose  measurements,  together  with  those 
of  our  private-school  children,  we  will  now  compare  with  the  earlier 
data  we  have  selected,  came  from  a  different  social  and  economic 
plane  of  life  than  our  private-school  children.  This  is  important  to 
bear  in  mind  in  the  following  comparisons,  since  it  has  been  shown 
many  times  that  the  development  of  the  child  depends  on  his  social 
surroundings  as  well  as  upon  his  physical  well-being.  In  the  several 
charts  now  to  be  considered,  since  we  have  but  a  few  scattered  obser- 
vations with  our  own  boys  beyond  13  years  of  age  and  with  our  own 
girls  beyond  12  years  of  age,  we  have  stopped  the  curves  representing 
our  measurements  at  13  years  for  boys  and  at  12  years  for  girls. 

RELATIONSHIP  BETWEEN  BODY-WEIGHT  AND  AGE  WITH  BOYS. 

As  an  index  of  the  state  of  nutrition  of  children,  the  relationship 
between  body-weight  and  age  is  perhaps  one  of  the  oldest  and  earliest 
relationships  which  have  been  considered.  This  ratio  of  body-weight 
alone  to  age  obviously  does  not  take  into  account  the  very  important 
factor  of  skeletal  growth  or  length.  Still,  as  it  represents  one  of  the 
earliest  relationships  utilized,  and  as  it  has  been  the  basis  of  a  large 
number  of  weight  charts  of  various  types,  it  requires  special  considera- 
tion. In  figure  3,  therefore,  we  have  plotted  curves  for  weight  referred 
to  age  for  boys,  representing  our  own  laboratory  measurements,  those 
in  the  two  earlier  European  studies  of  Quetelet  and  Schmid-Monnard, 
the  combined  Crum-Wood  data  compiled  by  Gray,  the  material  from 
Holt,  and  the  values  for  the  private-school  boys  measured  under  our 
direction. 

The  relative  positions  of  these  curves  are  of  very  great  significance. 
The  curves  of  the  two  foreign  investigators  lie  throughout  practically 
their  entire  length  measurably  below  the  curve  for  our  laboratory 
boys,  which  may  undoubtedly  in  part  be  explained  by  the  fact  that 
they  represent  entirely  different  nationalities.  Between  themselves 
they  agree  reasonably  well.  Of  singular  significance  is  the  fact  that 
the  combined  curve  of  Crum  and  Wood  is  almost  identical  with  our 
laboratory  curve.  It  is  very  important  to  note  that  below  4  years  of 
age  our  laboratory  boys  measure  up  essentially  to  the  standard  set 
by  this  curve,  although,  as  has  been  pointed  out  before,  Crum's 
children  are  considered  by  him  to  be  somewhat  supernormal.  A 
number  of  our  children  at  this  age  were,  however,  the  offspring  of 
resident  wet-nurses.  Holt's  curve  for  private-school  boys  is  measur- 
ably above  the  line  for  our  laboratory  boys  and,  indeed,  above  the 
continuation  of  the  Crum-Wood  curve  after  the  thirteenth  year, 
while  the  curve  for  our  private-school  boys  lies  even  higher  than  that 
of  Holt.  In  the  case  of  these  private-school  children  we  have  distinctly 
larger  and  heavier  boys  for  the  same  age,  as  is  unquestionably  shown 


40   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


by  these  two  curves.  It  is  important  to  bear  in  mind  here  that  the 
Holt  curve  is  derived  from  1,774  measurements,  while  our  private- 
school  curve  is  based  upon  886  measurements.  Holt's  values  repre- 
sent a  city  school,  attended  by  children  of  a  social  status  somewhat 
better  than  average,  who  received  better  medical  treatment  and  were 
unquestionably  living  in  better  hygienic  surroundings  than  the  average 


Kgs 

70 

65 
60 
55 
50 
45 
40 
35 
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WEIGHT   REFERRED  TO  AGE.               BOYS. 

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FIG.  3. — Relationship  between  body-weight  and  age  with  boys. 

child.  Our  private-school  boys  were  likewise  of  a  superior  social 
status,  received  better  medical  attention,  and  more  especially  indulged 
in  a  considerable  amount  of  active  outdoor  exercise,  all  of  which  factors 
make  for  a  distinctly  heavier  boy  for  a  given  age.  One  of  the  private 
schools  was  an  open-air  school.  The  influence  of  outdoor  life  and 
social  environment  is  so  striking  here  that  we  have  continued  our 
curve  for  private-school  children  to  the  age  of  18  years,  at  which 
point  our  collection  of  data  ends. 

While,  therefore,  our  curve  for  laboratory  boys  is  practically  identi- 
cal with  that  of  Crum  and  Wood  and  measurably  higher  than  the  curves 
of  the  foreign  authorities,  Quetelet  and  Schmid-Monnard,  it  is  dis- 
tinctly lower  than  the  two  curves  for  the  private  schools,  which  repre- 


NORMALITY   OF   CHILDREN    STUDIED. 


41 


sent  the  selected  classes.  Since  the  Crum-Wood  curve  is  derived 
from  measurements  of  several  thousand  American  children,  it  is  clear 
that  we  may  state  with  perfect  propriety  that,  so  far  as  this  classic 
relationship  of  body-weight  to  age  is  concerned,  our  laboratory  boys 
are  normal  as  compared  with  the  average  American  child,  but  are 
inferior  to  the  selected  class  of  private-school  boys,  who  are  distinctly 
heavier  than  other  boys  of  the  same  age.  In  fact,  at  the  age  of  12 
years  we  see  that  the  average  weight  of  our  laboratory  boys  is  about 
34.5  kg.,  while  the  average  weight  of  our  private-school  boys  is  about 
40  kg.,  a  very  perceptibly  greater  weight. 

RELATIONSHIP  BETWEEN  HEIGHT  AND  AGE  WITH  BOYS. 
An  intelligent  understanding  of  the  difference  noted  in  the  weight- 
to-age  ratios  of  our  laboratory  boys  and  the  private-school  boys  can 


Cms. 


HEIGHT   REFERRED  TO  AGE- 


BOYS. 


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FIG.  4. — Relationship  between  height  and  age  with  boys. 

not  be  had  until  we  have  some  conception  of  the  relative  heights  of 
these  boys.  Are  these  private-school  boys  heavier  because  they  are 
taller,  or  is  the  weight  independent  of  height?  To  answer  this  question 
we  will  consider  next  the  relationship  of  height  to  age  for  boys,  as 
pictured  in  figure  4,  where  we  have  exactly  the  same  sets  of  observa- 


42   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

tions  used  in  figure  3  and  exactly  the  same  comparison  will  be  made 
throughout  the  entire  age-range.  Using  our  own  laboratory  curve  as 
the  basis  for  comparison,  we  note  that  it  lies  throughout  the  entire 
length  above  the  two  foreign  curves,  thus  indicating  that  our  boys  are 
consistently  taller  for  their  age  than  are  the  foreign  boys.  Comparing 
our  curve,  however,  with  the  Crum-Wood  curve,  we  see  that  between 
about  2  years  and  4  years  our  boys  are  somewhat  shorter  than  the 
average.  From  that  point  on  the  deviations  in  our  curve  above  or 
below  the  Crum-Wood  curve  are  such  as  to  indicate  for  the  most  part 
uniformity  between  the  two  curves.  Special  attention,  however,  is 
called  to  that  portion  of  the  Crum-Wood  curve  representing  the  age 
range  below  4  years,  as  this  portion  is  derived  from  Crum's  measure- 
ments, which  represent  "supernormal"  infants.  It  is  clear,  there- 
fore, that  the  average  boy  as  measured  by  Crum  is  slightly  taller  for 
his  age  than  are  our  laboratory  boys;  in  other  words,  there  is  possibly 
a  slight  tendency  for  our  boys  to  be  under  height,  notably  so  at  about 
3  years  of  age. 

The  data  for  Holt's  private-school  boys,  and  likewise  for  our  private- 
school  boys,  here  again  show  marked  superiority  over  the  data  for  our 
laboratory  boys  and  over  the  Crum-Wood  average.  The  private- 
school  boys,  therefore,  are  not  only  heavier  for  their  age  but  likewise 
taller.  In  other  words,  the  private-school  boys  are,  from  the  age  of 
8  years  (where  our  study  of  them  begins)  and  older,  distinctly  larger 
individuals  both  in  height  and  in  weight  than  the  average  boy  of  the 
same  age. 

RELATIONSHIP  BETWEEN  BODY-WEIGHT  AND  AGE  WITH  GIRLS. 

Having  examined  the  findings  for  boys,  we  may  now  consider  the 
values  for  girls,  first  from  the  historic  standpoint,  i.  e.,  of  the  relation- 
ship between  body-weight  and  age.  This  weight-age  ratio  is  shown 
in  figure  5.  Fortunately,  we  have  practically  as  many  curves  for  girls 
as  for  boys  and  from  the  same  sources.  The  Holt  values,  however, 
are  missing,  as  Holt's  study  was  with  boys  only.  Our  own  private- 
school  data,  however,  include  323  girls  and  are  fairly  representative. 
The  line  representing  our  laboratory  studies  shows  that  the  body- 
weights  of  our  girls  are  noticeably  above  those  of  the  foreign  girls 
until  the  age  of  1 1  years  is  reached.  At  this  point  the  Schmid-Monnard 
curve  distinctly  begins  to  rise  above  our  curve.  There  is  no  suggestion 
of  an  upward  trend  in  our  curve  at  this  point,  although  our  data  beyond 
12  years  are  not  sufficient  to  indicate  what  the  further  trend  would  be. 
Up  to  8  years  our  curve  lies  slightly  above  the  Crum-Wood  line,  which 
is  considered  to  represent,  for  the  age-range  below  4  years,  a  rather 
superior  order  of  children.  After  8  years,  however,  it  is  apparent 
from  this  chart  that  our  laboratory  girls  are  probably  somewhat  under 
weight  for  their  age  when  compared  to  the  American  average  of  Crum 


NORMALITY   OF   CHILDREN   STUDIED. 


43 


and  Wood.    This  fact  must  be  carefully  considered  in  any  subsequent 
discussion  of  results. 

The  picture  exhibited  by  the  study  of  boys  in  private  schools  s 
duplicated  almost  exactly  here  in  the  case  of  girls  in  private  schools, 
where  a  superiority  in  the  weight-age  ratio  is  exhibited  all  along  the 
line  from  10  to  18  years  of  age.  Clearly  with  girls,  as  with  boys,  this 


Kgs 

60 

55 
50 
45 
40 
35 
30 
25 
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WEIGHT   REFERRED  TO  AGE.                GIRLS- 

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FIG.  5. — Relationship  between  body-weight  and  age  with  girls. 

superiority  may  be  explained  either  by  the  fact  that  private-school 
life  results  in  the  development  of  excessively  heavy  children  or  that 
the  children  attending  private  schools  represent  a  selected  class  enjoy- 
ing better  economic  conditions  favoring  growth. 

RELATIONSHIP  BETWEEN  HEIGHT  AND  AGE  WITH  GIRLS. 

Finally,  we  have  to  consider  the  relationship  between  height  and 
age  with  girls.  This  ratio  is  shown  in  figure  6.  In  this  figure  the 
curve  for  our  laboratory  girls  shows  that  on  the  whole  their  heights 
are  measurably  above  both  foreign  standards  up  to  about  8  years  of 
age,  but  only  slightly  above  the  Crum-Wood  standard.  Beyond  the 
age  of  8  years  our  data  agree  very  closely  with  both  the  Schmid- 
Monnard  and  Crum-Wood  series,  but  are  perceptibly  below  the  private- 
school  series.  While,  therefore,  our  girls  exhibit  a  slight  underweight 
above  8  or  9  years  of  age  when  compared  with  the  American  average, 


44   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


Cms.                 HEIGHT   REFERRED  TO  AGE- 

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FIG.  6. — Relationship  between  height  and  age  with  girls. 

they  do  not  exhibit  a  corresponding  underheight.  Hence  it  appears 
(although  this  is  not  the  place  for  discussion)  that  our  girls  were 
slightly  under  weight  on  the  basis  not  only  of  age  but  likewise  of  height. 
The  private-school  girls,  as  in  all  the  other  curves  where  the  private- 
school  children  are  charted,  show  a  clear  superiority  in  height  for  age. 

GENERAL  CONSIDERATION  OF  THE  RATIOS  OF  WEIGHT  TO  AGE  AND 
HEIGHT  TO  AGE  WITH  BOYS  AND  GIRLS. 

From  figures  3,  4,  5,  and  6  it  appears  that  the  data  for  our  laboratory 
children  agree  for  the  most  part  very  closely  with  the  average  values 
found  by  Crum-Wood  for  these  ratios,  and  that  they  are  in  general 
notably  above  the  measurements  of  the  two  foreign  observers,  although 
in  the  case  of  our  girls  there  is  inferiority  in  weight  after  the  age  of 
8  years.  The  private-school  data,  on  the  other  hand,  both  Holt's 
and  our  own,  indicate  superiority  not  only  in  weight  for  age,  but 
likewise  in  height  for  age  throughout  the  entire  age-range  studied. 
This  speaks  for  a  distinctly  better  type  of  youth  in  our  private  schools. 
It  is  questionable  whether  this  is  due,  first,  to  the  growth  actually 
made  in  the  private  schools  during  the  course  of  time,  or  to  the  fact 
that  the  children  entering  private  schools  come  from  a  better  class  of 
people,  from  a  better  social  economic  plane,  and,  particularly,  receive 


NORMALITY   OF   CHILDREN   STUDIED.  45 

better  medical  care.  Judged,  therefore,  by  these  old  standards  of 
height  to  age  and  weight  to  age,  our  laboratory  children  measure  up 
to  normal  (average)  in  practically  every  instance,  except  in  the  case 
of  the  weights  of  our  girls  8  years  of  age  and  above,  but  they  do  not 
measure  up  to  the  superior  type  of  child  found  in  the  private  schools 
in  the  environs  of  Boston. 

RELATIONSHIP  BETWEEN  HEIGHT  AND  BODY-WEIGHT  WITH 
BOYS  AND  GIRLS. 

With  adults,  no  one  would  think  of  considering  the  relationship 
between  weight  and  age  or  height  and  age  as  of  any  particular  sig- 
nificance, but,  singularly  enough,  with  children  these  two  ratios, 
particularly  that  of  weight  to  age,  have  long  held  the  attention  of 
physiologists  to  the  exclusion  of  almost  every  other  method  of  com- 


HEIGHT  REFERRED  TO    BODY  WEIGHT. 


BOYS. 


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FIG.  7.  —  Relationship  between  height  and  body-weight  with  boys. 

parison.  With  adults,  the  comparison  of  height  to  weight  has  long 
been  known  to  be  a  comparatively  good  index  of  the  state  of  nutrition. 
If  the  individual  is  very  tall  and  light  in  weight,  he  is  obviously  under- 
nourished; if  he  is  very  short  and  heavy  in  weight,  he  is  obese.  It 
seems  much  more  logical  to  consider  the  relationship  between  height 
and  weight  of  children  than  between  weight  and  age  or  height  and 
age.  Consequently  we  have  plotted  on  our  chart  (fig.  7)  the  values 
representing  the  height  referred  to  weight  for  our  laboratory  boys. 
As  stated  on  page  37,  these  values  for  weight  and  height  may  be  found 


46   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

in  tables  27  and  28  (pages  116  and  120)  and  tables  12  and  13  (pages  54 
and  58) ;  they  represent,  in  many  instances,  not  individual  measure- 
ments, but  an  average  of  several  measurements,  at  a  particular  age  or 
weight.  On  this  chart  we  have  arbitrarily  sketched  a  curve  showing 
the  general  trend  of  this  relationship,  the  curve  (as  usual)  representing 
the  personal  judgments  of  five  different  individuals.  It  is  clear  from 
this  curve  that,  with  the  subjects  we  have  studied,  a  boy  with  a  height 
of  110  cm.  would  weigh  approximately  20  kg;  on  the  other  hand,  a 
boy  weighing  30  kg.  would  have  a  height  of  approximately  134  cm. 
It  is  especially  to  be  emphasized  that  this  chart  does  not  take  age  into 
consideration,  but  it  more  nearly  indicates  the  typical  proportions  of 
our  children.  Since  the  analysis  of  the  earlier  charts  demonstrated 
that  our  children  usually,  both  for  their  height  versus  age  and  weight 
versus  age,  measure  up  very  closely  with  the  Crum-Wood  standard,  it 
can  be  seen  that  the  curve  here  shown  on  figure  7  represents  not  far 
from  the  probable  usual  height-to-weight  relationship  of  boys. 


9™                                                      HEIGHT   REFERRED  TO  BODY  WEIGHT.                                                      GIRLS. 

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FIG.  8. — Relationship  between  height  and  body-weight  with  girls. 

Our  extensive  series  of  measurements  of  private-school  boys  enables 
us  to  plot  on  our  chart  (fig.  7)  also  the  smoothed  curve  showing  the 
general  trend  of  the  relationship  between  height  and  weight  of  these 
boys.  It  is  of  particular  interest  here  to  note  that  the  curve  showing 
the  relationship  between  height  and  weight  of  private-school  boys  lies 
at  all  points  above  that  showing  the  height-weight  ratio  for  our  labor- 
atory children.  The  conclusion  is,  therefore,  that  the  private-school 
boys  are  lighter  in  weight  for  the  same  height  than  are  our  laboratory 
boys.  This  striking  relationship  will  need  special  consideration. 


GROWTH.  47 

If  we  consider  the  same  character  of  data  with  our  laboratory  girls 
as  with  our  boys,  as  plotted  on  figure  8,  we  see  that  the  sketched  line 
indicating  the  trend  is  in  general  form  not  unlike  that  obtaining  for 
boys.  Here  again  we  have  added  the  curve  representing  our  private- 
school  girls,1  which  shows,  as  in  the  case  of  boys,  a  line  measurably 
higher  at  all  points  than  the  corresponding  line  for  our  laboratory 
girls.  In  other  words,  the  private-school  girls  are  on  the  average 
somewhat  lighter  in  weight  for  the  same  height  than  are  our  girls. 

This  particular  phenomenon  with  private-school  children  attracts 
especial  attention  here,  since  in  all  of  our  earlier  comparisons  on  the 
charts  indicating  the  ratios  of  height  to  age  and  weight  to  age  it- 
appears  as  if  the  private-school  children  enjoy  a  very  marked  superi- 
ority. They  are  taller  for  the  same  age  and  heavier  for  the  same  age. 
When,  however,  we  compare  the  height  to  weight  irrespective  of  age, 
we  find  that  our  laboratory  children  of  both  sexes  are  slightly  heavier 
for  the  same  height  than  are  our  private-school  children.  Thus  the 
seeming  superiority  of  the  private-school  children  may  to  a  large 
extent  be  questioned  as  not  truly  so  great  as  at  first  sight  appears. 
Our  analysis  has  not  been  carried  out  far  enough  to  prove  whether  or 
not  there  is  a  natural  relationship  between  weight  and  height  and 
children  are  heavier  because  they  are  taller.  But  when  we  consider 
the  general  configuration  of  children  as  a  whole,  we  find  that  our  labor- 
atory children,  both  boys  and  girls,  are  somewhat  heavier  for  the  same 
height  than  are  the  private-school  children;  on  this  basis,  therefore, 
it  would  appear  that  our  laboratory  children  of  both  sexes  are  some- 
what superior  to  the  private-school  children. 

From  the  critical  examination  of  all  these  data  it  seems  clear  that 
our  laboratory  children,  representative  as  they  are  of  the  institution 
rather  than  the  select  home,  are  on  the  whole  fully  up  to  the  best 
American  standards  based  upon  large  series  of  individuals.  The 
striking  superiority  in  height  to  age  and  weight  to  age  of  our  private- 
school  children  is  in  part  at  the  sacrifice  of  what  is  commonly  considered 
the  most  advantageous  relationship  between  height  and  weight. 

GROWTH. 

The  factors  determining  the  height  and  weight  are  so  subtle,  espe- 
cially during  the  years  of  adolescence,  that  they  probably  will  require 
final  analysis  by  the  biometrician,  but  for  this  analysis  to  be  effective 
there  should  be  a  very  much  larger  mass  of  data  at  hand  than  we  now 
possess.  Under  the  circumstances,  therefore,  we  can  best  secure  an 
indication  of  the  general  trend  of  the  relationships  between  these 

1  This  curve  for  our  private-school  girls  should  properly  begin  at  26  kg.,  as  the  data  below  26  kg. 
are  rather  limited.  Nevertheless,  the  curve  is  projected  below  26  kg.  to  16  kg.,  and  for  this 
section  of  the  curve  a  different  style  of  line  has  been  used  to  show  that  the  data  are,  strictly 
speaking,  insufficient  between  16  and  26  kg. 


48   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

growth  factors  from  our  graphs  and  the  sketched  curves  accompanying 
them.  Almost  immediately  the  fact  is  forced  upon  one  that  the  re- 
lationships between  height,  weight,  and  age  are  by  no  means  to  be 
considered  as  primarily  due  to  the  age  factor,  but  the  general  con- 
figuration of  the  body  will  indicate  whether  the  child  is  too  heavy  or 
too  light  for  his  height.  The  relationships  of  height  to  weight  are  of 
most  importance.  This  statement  is  not  to  be  interpreted  as  meaning 
that  the  height-to-age  ratio  and  the  weight-to-age  ratio  should  be 
ignored.  Still,  the  erroneous  ideas  to  which  the  consideration  of  the 
ratios  of  weight  or  height  to  age  alone  may  lead  one  are  well  brought 
out  in  the  discussion  of  our  charts.  Here  it  was  shown  that  although 
the  curves  for  the  private-school  children  indicated  apparently  a  great 
superiority  over  our  laboratory  children,  a  subsequent  analysis  of  the 
relationship  between  height  and  weight  alone  proved  that  the  superi- 
ority is  by  no  means  as  great  as  would  at  first  be  implied,  and,  at 
least  so  far  as  the  relation  of  height  to  weight  is  concerned,  the  private- 
school  children  are  not  superior  to  those  of  our  laboratory  series. 

The  anomalous  situation  raised  by  an  inspection  of  these  charts  leads 
at  once  to  a  consideration  of  the  question  of  growth,  for  it  is  during  the 
period  from  birth  to  puberty  that  we  have  the  greatest  changes  in 
growth,  both  in  height  and  in  weight.  Indeed,  it  has  been  stated 
that  a  young  infant  goes  through  physical  changes  in  two  or  three 
months  which  it  would  take  adults  several  years  to  equal.  From  the 
slopes  of  practically  all  of  our  curves  it  is  very  clear  that  the  rate  of 
growth  is  greatest  during  the  first  year  of  life  and  gradually  diminishes 
as  the  child  grows  older.  A  study  of  a  large  number  of  measurements 
shows  that  the  greatest  gain  in  weight  is  made  during  the  first  5  or  6 
months  of  life,  when  a  normal  infant  almost  doubles  its  birth-weight. 
During  the  second  6  months  of  life  an  infant  gains  approximately  the 
same  amount  of  weight  as  during  the  first  5  or  6  months;  but  whereas 
the  increase  in  weight  during  the  first  5  or  6  months  is  100  per  cent, 
in  the  second  6  months  of  life  it  is  only  about  50  per  cent.  During 
the  second  year  of  life  the  increase  in  weight  diminishes  to  approx- 
imately 25  per  cent,  and  in  the  third  year  it  is  less  than  20  per  cent, 
The  percentage  increase  in  height  becomes  less  and  less  with  increasing 
age,  somewhat  similar  to  that  noted  for  weight.  Thus,  the  increase 
is  about  21  per  cent  during  the  first  6  months  of  life,  14  per  cent  during 
the  second  6  months,  and  correspondingly  less  as  the  child  grows  older. 
With  these  general  principles  of  growth  our  curves  conform  in  general, 
particularly  the  curve  illustrating  the  weight-to-age  ratio. 

It  must  be  clearly  recognized  at  the  outset  that  growth  should  not 
be  interpreted  as  meaning  only  addition  of  flesh.  Growth  means  the 
skeletal  growth  as  well,  and  it  is  only  by  establishing  the  proportion 
between  the  skeletal  growth  and  the  addition  of  flesh  that  the  most 
intelligent  consideration  of  growth  can  be  made.  Among  the  numer- 


GROWTH.  49 

ous  factors  which  affect  growth,  nationality,  environment,  and  social 
status  and  the  quantity  and  quality  of  the  food  are  the  most  important. 
Environment  and  social  status  influence  the  quantity  and  quality  of 
the  food  and  also  determine  largely  the  medical  care  which  a  child 
receives.  This  latter  factor  in  itself  is  becoming  an  increasingly 
important  one  in  the  element  of  growth,  for  defects  in  both  anatomical 
and  in  dietetic  conditions  are  recognized  and  corrected  by  early  medi- 
cal attention. 

Influence  of  nationality  on  growth. — The  well-recognized  influence  of 
nationality  on  growth  must  be  taken  into  account  in  the  consideration 
of  the  normality  of  our  children.  Owing  to  the  cosmopolitan  character 
of  the  American  people  and  the  large  influx  of  European  blood,  nation- 
ality undoubtedly  plays  an  important  role  in  the  establishment  of  the 
American  standard,  but  for  comparison  with  our  curves  the  use  of 
standard  growth-curves  representing  nationalities  other  than  American 
is,  strictly  speaking,  precluded.  Certain  nations  are  known  to  be 
tall  and  well-developed,  while  others  are  typically  short.  Thus,  the 
Anglo-Saxon  race  and  certain  branches  of  the  Chinese  race  are  pro- 
nouncedly taller  than  other  nationalities,  while  the  Japanese  race  is 
characteristically  short.  A  superficial  comparison  of  the  data  from 
different  countries  reveals  the  fact  that  the  growth-curves  for  different 
races  of  men  are  by  no  means  identical;  indeed,  this  may  be  said  to 
be  true  even  for  similar  races  inhabiting  different  localities.  Even 
in  Japan  there  are  localities  where  the  people  are  much  taller  than  the 
general  run  of  the  inhabitants,  while  in  England  it  has  been  found  that 
the  average  weight  of  infants,  both  male  and  female,  in  London  is 
much  higher  than  that  of  infants  in  Leeds  and  slightly  higher  than  the 
average  weight  of  infants  throughout  the  whole  of  England.  Con- 
sequently, in  comparing  the  growth-curves  of  our  children  with  other 
growth-curves,  emphasis  has  been  laid  upon  the  American  data,  as 
American  data  alone  may  properly  be  used  in  this  study  of  normality. 

Influence  of  environment  and  social  status  on  growth. — It  has  been 
shown  by  various  authors  that  environment  and  social  status  play  a 
part  in  the  growth  of  children.  Those  children  who  live  much  of  the 
time  out  of  doors  and  whose  families  can  afford  to  supply  them  with 
good  and  sufficient  food  obtain  better  growth  than  children  of  the  same 
nationality  and  locality  who  have  not  the  same  opportunities.1  As 
early  as  1829,  Villerme2  concluded  that  stature  is  greater  and  growth 
sooner  completed,  all  other  things  being  equal,  in  proportion  as  the 
country  is  richer  and  the  comforts  of  the  inhabitants  more  general. 
Robertson3  reports  that  "increasing  unfavorability  of  environment 
results  in  a  parallel  increase  of  deficiency  in  weight  and  stature." 

1  Burk,  Am.  Journ.  Psychol.,  1898,  9,  p.  272. 

2  Villermfi,  Ann.  d'Hyg.  Pub.  et  de  M6d.  L6gale,  Paris,  1829,  1,  p.  351. 

3  Robertson,  Am.  Journ.  Physiol.,  1916,  41,  p.  553. 


50   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

He  also  notes  that  "as  the  favorability  of  the  environment  decreases, 
the  proportion  of  medical  care  extended  to  the  children,  as  indicated 
by  the  percentage  of  removed  adenoids,  also  decreases,  while  the  degree 
of  medical  neglect,  as  indicated  by  the  percentage  of  infected  and 
unoperated  adenoids,  undergoes  a  parallel  increase." 

Food  and  physical  surroundings  are  not  entirely  responsible  for 
under-growth.  It  has  been  shown  that  physical  defects  play  a  large 
part  in  preventing  the  normal  growth  and  nourishment  of  children, 
even  under  good  dietetic  and  hygienic  conditions.  Carious  and 
infected  teeth  and  enlarged  and  infected  tonsils  and  adenoids  are  the 
most  common  physical  defects  responsible  for  under-growth  and 
under-nourishment . 

Exercise. — Ordinarily  it  is  considered  that  the  effect  of  exercise  is 
almost  immediately  compensated  by  an  increased  food  consumption, 
as  commonly  experienced  in  the  ravenous  appetities  of  vigorously 
exercising  children,  yet  it  may  frequently  happen  that  an  underfed 
child  automatically  restricts  his  energy  expended  in  work  or  play  to  a 
lower  level,  in  order  to  provide  for  growth.  In  other  words,  a  child 
that  is  undernourished  can  not  supply  the  energy  for  vigorous  exer- 
cise, since  he  needs  this  energy  first  for  growth,  and  he  will  auto- 
matically cut  down  his  activity  and  thus  conserve  energy.  On  the 
other  hand,  a  child  may  be  led,  in  the  excitement  of  competition  with 
his  playmates,  to  excessive  exercise.  In  this  case  the  child  (although 
furnished  with  a  considerable  amount  of  food)  grows  in  height — in 
other  words,  the  skeletal  growth  continues — but  he  does  not  gain  in 
weight.  The  lack  of  growth  in  weight  in  this  instance  is  due  to 
excessive  exercise  and  to  the  fact  that  extra  food  has  not  been  added 
to  compensate  the  increased  muscular  activity.  If  such  a  child  is 
made  to  take  regular  rest  periods  during  the  day,  he  will  commence  to 
gain  weight  on  a  normal  diet  without  an  increase  in  the  quantity  of 
food. 

The  value  of  rest  in  conserving  the  energy  of  children  has  been  most 
tragically  illustrated  in  the  recent  experiences  of  German  mothers  in 
the  war,  as  reported  by  Leonard  Hill: 1 

"The  mothers  of  Germany  kept  their  war-starved  children  most  of  the 
day  in  bed,  letting  them  get  up  at  11  a.  m.  and  go  to  bed  at  4  p.  m.  Thus 
they  husbanded  the  national  life,  taught  by  scientific  experience  that 
growth  will  make  good  when  the  war  is  over  and  food  supplies  become 
ample." 

We  thus  see  that  the  amount  of  food  and  exercise  together  play  a 
very  important  part  in  the  final  resultant  growth,  and  that  while  the 
quantity  of  food  affects  the  general  state  of  nutrition,  it  is  not  the  sole 
cause  for  undernutrition.  If  the  caloric  intake  is  not  sufficient  to 

1  Hill,  The  science  of  ventilation  and  open-air  treatment,  part  i,  Special  Report  Series  No.  32, 
Medical  Research  Committee,  London,  1919,  p.  79. 


GROWTH.  51 

cover  the  energy  output  due  to  play  and  activity,  the  child  will  auto- 
matically restrict  his  activity  so  that  the  limited  amount  of  food  fur- 
nished will  provide  first  for  growth,  primarily  stature. 

The  relationship  between  food  and  height. — Too  much  emphasis  must 
not  be  laid  on  the  caloric  value  of  food  only.  It  is  becoming  increas- 
ingly evident  that  certain  unidentified  factors  in  the  food,  the  so-called 
"food  accessories"  or  popularly  termed  "vitamines,"  play  a  very 
important  role  in  skeletal  growth  and  the  subsequent  addition  of  tissue. 
Practically  all  of  our  knowledge  of  the  relationship  between  food  and 
height,  or  skeletal  growth,  has  been  obtained  from  observations  made 
by  the  American  investigators,  Osborne  and  Mendel,1  and  McCollum,2 
on  white  rats.  These  important  studies  have  shown  that  the  presence 
in  the  diet  of  the  as  yet  unidentified  "food-accessory  substances," 
popularly  termed  vitamines,  is  necessary  to  normal  skeletal  growth. 
If  these  "food  accessories"  are  absent,  there  is  a  stuntage  of  growth 
in  general,  but  development  is  not  particularly  abnormal.  Osborne 
and  Mendel  were  able,  by  the  removal  of  these  "food-accessory  sub- 
stances" from  the  diet,  to  defer  the  growth  of  white  rats  for  a  prolonged 
period.  Subsequently,  by  supplying  the  proper  foods  and  "food 
accessories,"  they  caused  these  same  white  rats  to  attain  normal 
growth  without  apparent  impairment  in  condition,  thus  proving  that 
the  growth  impulse  or  capacity  for  growth  may  be  suppressed  for  a 
time  and  exercised  later  at  a  period  far  beyond  the  age  at  which 
growth  usually  ceases.  Jackson  and  Stewart3  found  that  although 
different  organs  in  the  body  did  not  maintain  their  normal  relative 
weight  during  inanition,  after  the  proper  food  was  given  they  resumed 
their  natural  growth  and  attained  adequate  size  despite  the  early 
stunting.  Retarded  growth,  therefore,  does  not  necessarily  mean  that 
there  can  be  no  hope  of  attaining  perfect  adult  form  and  function; 
on  the  contrary,  when  organic  disease  is  absent,  there  is  every  reason 
to  believe  that  there  will  be  proper  restitution  on  a  correct  diet. 

Food  deficiencies  may  be  of  two  distinct  kinds.  First,  there  may 
be  an  absence  of  the  "food-accessory  substances"  which  promote 
growth;  second,  there  may  be  a  caloric  deficiency  which  manifests 
itself  chiefly  in  the  loss  of  previously  stored  body  material  or  in  a 
decrease  in  body  storage  or  growth  in  weight  during  the  growing  period. 
With  a  diet  insufficient  in  caloric  content,  but  in  which  the  "food- 
accessory  substances"  are  still  present,  skeletal  growth  continues  and, 
as  Waters4  has  shown,  even  if  the  diet  be  very  much  reduced  and  much 
below  that  required  for  maintenance,  there  will  still  be  a  long-continued 
skeletal  growth  without  corresponding  gain  in  weight.  Hence  it 
seems  as  if  in  the  long  run,  unless  children  are  greatly  undernourished 


1  Osborne  and  Mendel,  Carnegie  Inst.  Wash.  Pub.  No.  156,  1911. 

2  McCollum,  The  newer  knowledge  of  nutrition,  New  York,  1918. 

3  Jackson  and  Stewart,  Am.  Journ.  Diseases  Children,  1919,  17,  p.  329. 

4  Waters,  Proc.  Soc.  Promotion  Agr.  Sci.,  1908,  29,  p.  3. 


52   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

and  their  diet  is  woefully  deficient  in  the  " food-accessory  substances," 
they  will  have  a  reasonably  normal  skeletal  growth  with  increasing 
age.  It  is  at  this  point  that  we  note  the  special  significance  of  the 
time-honored  early  consideration  of  the  relationship  of  height  to  age. 
If  the  height  is  not  up  to  that  ordinarily  found  for  the  age,  then  we 
may  reasonably  assume  that  the  " food-accessory  substances"  in  the 
diet  are  deficient,  unless  we  are  dealing  with  an  abnormal  class  of 
individuals  containing  a  large  number  of  foreign  population  of  normally 
short  stature.  If  the  height  is  equal  to  that  normally  found  for  the 
age  but  the  weight  is  too  low  for  the  height,  we  may  then  look  for  a 
deficiency  in  the  caloric  intake — that  is,  the  calories  ingested  are 
not  sufficient  to  take  care  of  the  heat  output  existing  at  the  time, 
and  while  food  may  be  ample  for  normal  exercise,  with  excessive 
exercise  there  is  deficiency  in  growth.  Here  we  have  the  situation 
which  is  so  popularly  expressed  by  the  statement  that  the  boy  "runs 
himself  as  thin  as  a  rail." 

From  the  foregoing  consideration  of  the  several  factors  affecting 
growth,  it  can  be  seen  that  a  study  of  our  growth-curves  on  the  whole — 
that  is,  of  our  height-age,  weight-age,  and  height-weight  ratios — is 
probably  involved  by  the  question  of  nationality,  the  question  of 
environment  and  social  status  as  reflected  in  the  food,  exercise,  and 
medical  care,  the  question  of  " food-accessory  substances"  in  the  diet, 
and  the  caloric  intake.  Some  of  these  questions,  certainly  that  of 
nationality  and  medical  care,  are  extremely  difficult  to  consider 
separately.  From  our  curves,  however,  certain  deductions  may 
legitimately  be  drawn.  In  the  first  place,  we  have  seen  that,  based 
on  the  relationship  of  height  to  age  and  weight  to  age,  our  laboratory 
children  as  a  whole,  both  boys  and  girls,  measure  up  to  the  best  and 
most  representative  standard  of  American  children,  i.  e.,  the  data  of 
Crum  and  Wood,  but  that  in  neither  of  these  relationships  do  they 
measure  up  to  the  private-school  children,  either  those  studied  by 
Holt  or  by  ourselves.  It  appears,  therefore,  that  the  private-school 
children  are  taller  and  heavier  for  their  age;  but  a  subsequent  con- 
sideration of  the  relationship  between  height  and  weight  shows  that 
on  the  whole  they  are  a  little  thinner  for  the  same  height  than  are  our 
children. 

ANTHROPOMETRIC  MEASUREMENTS  AS  INDICES  OF  GROWTH. 
From  a  careful  consideration  of  the  various  relationships  between 
height,  weight,  and  age  we  are  convinced  that  the  best  ratio  to  indicate 
the  normal  state  of  nutrition  is  that  of  height  to  weight.  Still,  in  a 
subject  as  important  as  this,  it  is  desirable  to  make  use  of  every 
conceivable  measurement  that  may  possibly  contribute  towards  clari- 
fying the  problem  as  to  what  is  the  normal  state  of  nutrition.  Many 
writers  have  used,  in  addition  to  height  and  weight,  typical  measure- 


GROWTH.  53 

ments,  such  as  the  girth  around  the  chest  or  the  abdomen  at  the 
level  of  the  umbilicus,  the  height  of  the  subject  when  sitting,  and 
other  measurements.  Pediatricians  have  not,  however,  accepted  any 
of  these  generally.  To  show  at  a  glance  whether  the  individual  is  well 
nourished  or  poorly  nourished  we  need  some  mathematical  expression 
of  relationship  between  either  weight  or  height  and  one  or  more 
girths.  In  other  words,  some  quantitative  device  is  needed  for  con- 
firming the  personal  opinion,  which  is  only  too  frequently  based  upon 
superficial  inspection. 

For  an  entirely  different  purpose,  i.  e.,  primarily  to  compute  the 
body-surface  of  our  subjects  by  the  extremely  ingenious  linear  formula 
of  Du  Bois,1  we  made  a  large  number  of  measurements  of  various  parts 
of  the  body.  Many  of  these  are,  it  is  true,  not  those  conventionally 
recorded  by  anthropometers,  but  a  number  do  give  indications  of 
growth  and  are  of  general  as  well  as  special  value.  Of  the  numerous 
measurements  required  by  the  Du  Bois  linear  formula,  we  believe  we 
are  warranted  in  publishing  only  two,  namely,  the  circumferences  at 
the  nipples  and  at  the  hips  and  buttocks.  Consequently,  in  tables  12 
and  13,  in  addition  to  the  age,  height,  and  weight  of  each  child,  we 
have  given  these  two  circumferences.2  These  are  included  hi  our 
tables  as  much  for  the  benefit  of  the  future  biometrician  as  for  our  own 
immediate  use.  The  circumference  at  the  umbilicus  seemed  to  us  too 
dependent  upon  accidental  conditions  (such  as  food  in  the  stomach  and 
gas  in  the  intestines)  to  bring  it  into  the  same  anthropometrical  order 
of  value  as  either  of  the  other  measurements,  although  obviously  the 
chest  measurement  has  its  own  inherent  errors. 

Finally,  we  have  recorded  in  the  last  three  columns  of  these  same 
tables  the  results  of  our  study  of  body-surface  measurements  by  two 
different  methods.  The  surface  areas  by  the  Du  Bois  linear  formula 
were  obtained  primarily  to  throw  light  upon  the  possible  relationship 
between  body-surface  and  basal  heat-production.  While  we  firmly 
believe  that  this  relationship  has  been  very  much  overestimated  and 
its  significance  certainly  grossly  misunderstood,  it  still  remains  a 
fact  that  as  a  general  index  of  growth  the  body-surface  may,  the- 
oretically at  least,  be  of  a  somewhat  higher  degree  of  importance  than 
the  body-weight.3 

i  Du  Bois  and  Du  Bois,  Arch.  Intern.  Med.,  1915,  IS,  p.  868. 

s  The  data  given  in  tables  12  and  13  were  not  used  in  plotting  our  various  charts  showing  the 
relationships  between  age,  weight,  height,  and  body-surface  (except  in  the  case  of  8  boys  and 
4  girls  especially  noted  in  the  tables).  The  values  in  these  tables  represent  individual 
measurements  in  every  case  and  not  average  values.  The  selection  of  data  for  each  child 
was  made  on  the  basis  solely  of  an  increase  in  body-weight  of  1  kilogram.  The  values, 
therefore,  differ  somewhat  from  those  for  similar  body  measurements  given  in  tables  26, 
27,  and  28  (pages  112,  116,  and  120)  which  represent  chiefly  average  values. 

3  For  a  consideration  of  the  significance  of  the  relationship  between  body-weight  and  the  two- 
thirds  power  of  the  body-weight  with  other  morphological  measurements,  see  Dreyer  and 
Ray,  Phil.  Trans.,  1909-1910,  201,  ser.  B.,  p.  133;  ibid.,  Phil.  Trans.,  1911,  202,  ser.  B.t 
p.  191;  Dreyer,  Ray,  and  Walker,  Proc.  Roy.  Soc.,  1912-1913,  86,  ser.  B.,  pp.  39  and  56. 
See  also  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914,  p.  168. 


54   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


TABLE  12. — Body-girths  of  boys  and  comparison  of  body-surfaces,  as  measured  by  the  Du  Bois 
linear  formula  and  as  computed  from  the  formula  K\w2. 


Sub- 
ject 
No. 

Age. 

Body- 
weight 
(with- 
out 
cloth- 
ing). 

Height. 

Circumference. 

Body-surface. 

At 
nipples. 

At  hips 
and 
but- 
tocks. 

Du  Bois 
linear. 

K3w*. 
(') 

Per 
cent  de- 
viation 
from 
Du  Bois 
linear. 

107 
108 

1.4  g 

106 
114 
115 
27 
6 
117 
61 
118 
115 
119 
137 
125 
124 
132 
133 
118 
125 
115 
126 
119 
130 
141 
132 
128 
147 
155 
148 
136 
161 
115 
159 
129 
157 
119 
153 
164 
156 
150 
148 
158 
126 

9  days 

kilos. 
3.32 
3.40 
3.60 
3.83 
3.83 
3.83 
3.86 
4.54 
4.54 
4.60 
4.71 
4.71 
4.96 
5.03 
5.03 
5.09 
5.47 
5.48 
5.66 
5.74 
5.77 
5.79 
5.97 
6.02 
6.24 
6.24 
6.35 
6.43 
6.53 
6.55 
6.56 
6.70 
6.83 
7.03 
7.08 
7.11 
7.19 
7.20 
7.30 
7.36 
7.45 
7.47 
7.48 
7.49 

cm. 
51.0 
50.5 
51.0 
53.0 
54.0 
55.0 
53.0 
52.0 
54.0 
56.0 
58.5 
58.5 
58.5 
60.0 
57.0 
57.0 
59.0 
61.0 
61.5 
60.5 
63.0 
60.0 
64.5 
63.0? 
61.5 
64.5 
61.5 
63.0 
68.0 
66.0 
66.5 
67.5 
65.0 
66.5 
62.0 
64.0? 
67.5 
67.0 
71.0 
65.5 
72.0 
68.0 
66.5 
66.5 

cm. 
*33 
233 

cm. 

sq.  m. 

sq.  m. 
0.222 

ll£  days 

.226 

11|  days 

.234 

8£  days 

*36 
*34 

34 

.245 

*33 

30 

.245 

0.243 

.245 
.246 

+0.82 

8f  days  
8  days 

274 

1|  mos  

38 
*38 
36 
35 
37 
*40 
37 
*40 
40 
39 
39 
39 
38 
40 
40 

33 
*30 
33 
34 
35 

.266 

.278 
.271 
.313 

.274 
.276 
.280 
.280 
.290 
.293 
.293 
.295 

+3.01 

'+".72 
+3.32 
-7.35 

-2.66 

2  mos  
1$  mos  
2|  mos  

1  mb.  lj  wks  

4  J  mos  

2  mos.  1  wk  

35 

.301 

2  mos.  1  wk.   . 

lj  mos.  .  . 

38 
37 
36 
39 
36 
40 
38 

.322 
.312 
.318 
.325 
.317 
.327 
.331 

.310 
.310 
.317 
.320 
.321 
.322 
.329 
.331 
.344 
.344 
.350 
.355 
.361 
.362 
.362 
.371 
.378 
.389 
.391 
.392 
.395 
.395 
.399 
.401 
.404 
.405 
.405 
.406 

-3.73 
-  .64 
-  .31 
-1.54 
+1.26 
-1.53 
-  .60 

3  mos  

3  mos.  1  wk. 

3  mos.  1  wk  

2  mos.  l£  wka  

4  mos  
3  mos  

4  mos.  1  wk  
3|  mos  
2  mos.  3  wks  
5  mos.  1  wk  
6  mos.  3  J  wks  
5  mos.  1  wk  

238 
40 
*39 
42 
39 
42 
40 
44 
41 
41 
"43 

•  '4y  • 

43 
*43 
43 

244 

43 

44 
41 

«40 

39 
*41 
40 
38 
42 
40 
40 
43 
42 

.340 

+1.18 

-8.97 
-5.74 
-4.49 
+1.69 
-6.08 
+1.07 
+4.01 

.390 
.383 
.379 
.356 
.395 
.374 
.374 

4  mos.  1  wk.  .  .  . 

7j  mos  

7  mos.  3  wks. 

7£  mos  

3  mos  

7  mos.  .  .    . 

41 
41 

42 
*38 
41 
44 
45 

.399 
.386 

.426 

.394 
.403 
.400 

-  1.00 
+2.33 

'  ^5.87' 

'+2.79 
+  .50 
+1.50 

6  mos.   . 

6  mos.  1  wk  
9  mos. 

7  mos. 

6  mos. 

7  mos.  .  . 

7  mos. 

6  mos  

1  For  values  of  K  see  table  14. 

2  The  measurements  noted  are  not  part  of  the  regular  series  of  Du  Bois  linear  measurements. 

They  are  entered  here  on  the  assumption  that  they  represent  measurements  similar  to  those 

taken  in  the  use  of  the  Du  Bois  linear  formula. 
8  The  data  for  this  subject  were  used  in  plotting  the  charts  shown  in  figures  3  to  11  (pp.  40 

to  66). 
'Previously  reported  as  O.  C.;   Benedict  and  Talbot,  Am.  Journ.  Diseases  of  Children,  1914, 

8,  p.  1. 


GROWTH. 


55 


TABLE  12. — Body-girths  of  boys  and  comparison  of  body-surfaces,  as  measured  by  the  Du  Bois 
linear  formula  and  as  computed  from  the  formula  K^w* — Continued. 


Sub- 
ject 
No. 

Age. 

Body- 
weight 
(with- 
out 
cloth- 
ing). 

Height. 

Circumference. 

Body-surface. 

At 
nipples. 

At  hips 
and 
but- 
tocks. 

DuBois 
linear. 

*,f 

Per 

cent  de- 
viation 
from 
DuBois 
linear. 

155 
154 
138 
119 
161 
136 
153 
158 
142 
148 
170 
149 
138 
158 
148 
168 
158 
138 
161 
153 
136 
142 
161 
153 
138 
148 
158 
119 
176 
153 
175 
158 
155 
119 
119 
153 
177 
182 
192 
»207 
186 
194 
197 
204 
199 
212 

10  mos  

kilos. 
7.56 
7.91 
7.94 
8.08 
8.09 
8.19 
8.44 
8.48 
8.78 
8.87 
9.20 
9.33 
9.53 
9.55 
9.76 
9.95 
10.0 
10.1 
10.1 
10.2 
10.6 
10.7 
10.9 
11.2 
11.3 
11.3 
11.7 
11.7 
12.2 
12.5 
12.5 
12.7 
12.7 
12.7 
13.6 
13.9 
14.6 
15.4 
18.8 
18.9 
19.3 
19.7 
19.9 
19.9 
20.2 
20.5 

cm. 
71.5 
66.0 
68.0 
70.5 
70.5 
71.0 
68.5 
70.5 
66.0 
72.0 
74.0 
75.0? 
74.5 
77.0 
78.0 
74.0 
81.0 
79.5 
77.5 
77.0 
76.5 
70.0 
80.5 
80.0 
82.0 
82.0 
82.0 
79.5 
87.5 
84.0 
82.0 
84.0 
90.0 
83.5 
90.5 
88.5 
88.5 
94.0 
106.0 
107.5 
110.5 
107.5 
114.0 
111.5 
115.5 
120.5 

41 
44 
43 
43 
43 
44 
46 
45 
45 
45 

em. 
43 
45 
46 
45 
45 
41 
45 
45 
49 
45 

sq.  m. 
0.412 
.434 
.414 
.409 
.419 
.427 
.435 
.449 
.442 
.435 

sq.  m. 
0.408 
.421 
.422 
.427 
.427 
.431 
.439 
.441 
.451 
.454 
.466 

-0.97 
-3.00 
+1.93 
+4.40 
+1.91 
+  .94 
+  .92 
-1.78 
+2.04 
+4.37 

65  mos  

4  mos.  3  wks. 

7j  mos. 

8  mos.  3  wks. 

11  mos.  3  wka  

4  mos  

8f  mos  

10  mos  
55  mos  

.470 
.476 
.477 
.484 
490 

+6.73 
-1.24 
+5.68 

10  mos.  3$  wks  
1  yr.  6  mos  

46 
47 
47 
*46 
48 
48 
48 
48 
50 
49 
50 
50 
49 
49 
51 
50 
53 
51 
52 
51 
50 
52 
52 
51 
55 
55 
58 
59 
59 
59 
57 
59 
60 
61 

46 
45 
44 

.446 
.483 
.458 

12i  mos. 

9j  mos. 

44 
46 
49 
47 
49 
50 
49 
50 
49 
47 
51 
52 
48 
51 
49 
53 
50 
54 
54 
52 
52 
55 
57 
58 
58 
60 
58 
60 
57 
58 

.510 

.508 
.509 
.505 
.509 
.530 
.542 
.553 
.552 
.521 
.541 
.541 
.575 
.570 
.552 
.562 
.568 
.609 
.624 
.611 
.608 
.649 
.758 
.804 
.829 
.820 
.799 
.820 
.812 
.882 

.492 
.495 
.495 
.498 
.511 
.514 
.521 
.530 
.534 
.534 
.546 
.546 
.562 
.571 
.571 
.577 
.577 
.577 
.604 
.613 
.633 
.671 
.791 
.794 
.805 
.817 
.822 
.822 
.831 
.839 

-3.53 
-2.56 
-2.75 
-1.39 
+  .39 
-3.02 
-3.87 
-4.16 
-3.26 
+2.50 
+  .92 
+  .92 
-2.26 
+  .18 
+3.44 
+2.67 
+1.58 
-5.25 
-3.21 
+  .33 
+4.11 
+3.39 
+4.35 
-1.24 
-2.90 
-  .37 
+2.88 
+  .24 
+2.34 
-4.88 

1  yr.  4  mos.  85  wks  
1  yr.  2  mos  

9  mos  

8  mos.  l£  wks  
1  yr.  4§  mos  

2  yrs  
1  yr.  10  mos.  3  wks  
1  yr.  5  mos  

2  yrs.  6  mos.  1  wk  
1  yr.  1  mo.  3  wks. 

2  yrs.  4  mos.  3|  wks.  .  .  . 
2  yrs.  5  mos.  1  wk  
2  yrs   10  mos 

2  yrs.  6  mos  

1  jr.  6  mos  

2  yrs.  1  mo  
3  yrs.  2  wks  
2  yrs.  7  mos.  2  wks  
4  yrs  
5  yrs.  6  mos.  3  wks  
7  yrs.  7  mos.  2  wks  
4  yrs.  8  mos.  3  wks  
5  yrs.  9  mos.  1  wk. 

6  yrs.  9  mos.  3  wks  

6  yrs.  10  mos.  2  wks.  .  .  . 
8  yrs.  1  mo  

1  For  values  of  K  see  table  14. 

2  The  measurements  noted  are  not  part  of  the  regular  series  of  Du  Bois  linear  measurements. 

They  are  entered  here  on  the  assumption  that  they  represent  measurements  similar  to  those 
taken  in  the  use  of  the  Du  Bois  linear  formula. 

3  The  data  for  this  subject  were  used  in  plotting  the  charts  shown  in  figures  3  to  11  (pp.  40 

to  66). 


56   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


TABLE  12. — Body-girths  of  boys  and  comparison  of  body-surfaces,  as  measured  by  the  Du  Bois 
linear  formula  and  as  computed  from  the  formula  K^w2 — Continued. 


Sub- 
ject 
No. 

Age. 

Body- 
weight 
(with- 
out 
cloth- 
ing). 

Height. 

Circumference. 

Body-surface. 

At 
nipples. 

At  hips 
and 
but- 
tocks. 

Du  Bois 
linear. 

K3vfi. 

M 

Per 

cent  de- 
viation 
from 
Du  Bois 
linear. 

187 
215 
205 
2213 
201 
2200 
2208 
193 
2231 
2216 
201 
2226 
218 
222 
209 
224 
202 
223 
217 
218 
242 
211 
232 
228 
244 
253 
235 
229 
247 
249 
241 
236 
245 
240 
256 
252 
237 
246 
243 
259 
255 
254 
260 
250 
258 

5  yrs.  3  wks. 

kilos. 
20.6 
20.7 
21.3 
21.5 
21.8 
22.0 
22.6 
23.7 
24.0 
24.1 
24.2 
24.6 
24.8 
25.0 
25.2 
25.6 
25.8 
25.9 
26.6 
26.8 
26.8 
26.9 
28.2 
28.6 
29.5 
30.0 
30.1 
30.4 
30.5 
30.6 
30.6 
31.3 
31.4 
33.6 
33.7 
34.1 
34.4 
36.7 
37.9 
37.9 
37.9 
39.2 
39.2 
41.1 
51.1 

cm. 
111.0 
116.5 
117.5 
119.5 
122.5 
123.0 
118.0 
118.0 
122.5 
123.5 
124.0 
122.0 
128.5 
122.5 
125.5 
126.0 
121.0 
129.0 
123.5 
133.5 
126.0 
129.0 
127.0 
126.5 
132.0 
139.0 
134.0 
128.0 
141.0 
135.5 
136.0 
132.5 
135.5 
138.5 
137.5 
139.0 
139.5 
150.5 
149.5 
151.5 
153.0 
151.0 
147.0 
150.5 
159.5 

cm. 
57 
59 
60 
64 
60 
62 
60 
62 
63 
61 
61 
62 
62 
64 
63 
63 
64 
63 
64 
62 
65 
68 
69 
65 
66 
67 
67 
70 
66 
68 
66 
70 
69 
70 
69 
69 
68 
72 
73 
73 
68 
72 
72 
73 
83 

cm. 
58 
61 
60 
57 
59 
59 
64 
64 
62 
61 
62 
64 
64 
63 
64 
63 
63 
63 
65 
66 
64 
65 
67 
68 
67 
66 
68 
69 
67 
70 

70 
69 
72 
71 
72 
72 
71 
75 
75 
76 
74 
74 
79 
83 

sq.  m. 
0.832 
.838 
.887 
.872 
.874 
.876 
.873 
.904 
.976 
.976 
.934 
.926 
.953 
.942 
1.009 
1.025 
.939 
.991 
.965 
.988 
.985 
1.045 
1.090 
.998 
1.082 
1.089 
1.084 
1.057 
1.153 
1.183 
1.100 
1.103 
1.166 
1.237 
1.224 
1.245 
1.217 
1.256 
1.256 
1.341 
1.303 
1.335 
1.303 
1.368 
1.493 

sq.  m. 
0.842 
.845 
.861 
.866 
.874 
.879 
.895 
.924 
.932 
.935 
.937 
.948 
.953 
.958 
.968 
.989 
.999 
1.004 
1.025 
1.030 
.030 
.032 
.065 
.076 
.098 
.110 
.113 
.120 
.123 
.125 
.125 
.142 
.145 
.197 
.200 
.209 
.216 
.270 
.298 
.298 
.298 
.327 
1.327 

+1.20 

+  .84 
-2.93 
-  .69 
±0.00 
+  .34 
+2.52 
+2.21 
-4.51 
-4.20 
+  .32 
+2.38 
±0.00 
+  1.70 
-4.06 
-3.51 
+6.39 
+  1.31 
+6.22 
+4.25 
+4.57 
-1.24 
-2.29 
+7.82 
+  1.48 
+  1.93 
+2.68 
+5.96 
-2.60 
-4.90 
+2.27 
+3.54 
-1.80 
-3.23 
-1.96 
-2.89 
-0.08 
+  1.11 
+3.34 
-3.21 
-  .38 
-  .60 
+1.84 

7  yrs.  2  mos.  1  wk  
8  yrs.  1  mo.  3?  wks  
6  yrs.  11  mos.  3?  wks.  .  . 
6  yrs.  11  mos.  3  wks.  .  .  . 

5  yrs.  7  mos.  3  wks  
10  yrs.  3  mos.  3  wks  
8  yrs.  4  mos.  35  wks.  .  .  . 
7  yrs.  3  mos.  2|  wks.  .  .  . 
9  yrs.  5j  mos  

8  yrs.  63  mos  
9  yrs.  3i  wks  
7  yrs.  10  mos.  1|  wks.  .  . 
9  yrs.  3  mos.  3  wks  
7  yrs.  2  mos  
9  yrs.  1  mo.  2  wks  

8  yrs.  6  mos  

9  yrs.  5?  mos  
11  yrs.  2  mos.  1|  wks.  .  .  . 
8  yrs.  3  wks.  .  . 

10  yrs.  4  mos. 

9  yrs.  9  mos.  3  wks  
11  yrs.  4  mos.  1?  wks.  .  .  . 
12  yrs.  5  mos. 

10  yrs.  7  mos.  1  wk  
9  yrs.  10  mos.  3|  wks.  .  . 
11  yrs.  8  mos.  1  wk  
11  yrs.  11  mos.  3  wks.  .  .  . 
11  yrs.  lj  mos  

10  yrs.  8^  mos  
11  yrs.  5j  mos  
1  1  yrs.  1  mo.  1  wk  
12  yrs.  85  mos  
12  yrs.  3  mos.  2  wks  
10  yrs.  8  mos.  3|  wks.  .  .  . 
11  yrs.  6  mos  
11  yrs.  3  mos.  1$  wks.  .  .  . 
14  yrs.  1  mo  

12  yrs.  8  mos  
12  yrs.  7  mos.  3  wks  
15  yrs.  1  wk  

12  yrs.  l£  mos  
13  yrs.  8  mos  

1  For  values  of  K  see  table  14. 

2  The  data  for  this  subject  were  used  in  plotting  the  charts  shown  In  figures  3  to  11  (pp.  40 

to  66). 


GROWTH.  57 

With  regard  to  the  measurement  of  body-surface,  we  must  assume 
that  the  Du  Bois  linear  formula  gives  the  actual  areas  very  closely. 
A  note  of  caution  has  been  sounded,  however,  by  Du  Bois,1  who 
specifically  states  that  it  does  not  seem  advisable  to  use  this  formula 
for  infants  under  2  years  of  age  until  the  factors  have  been  tested 
by  the  measurements  of  other  infants.  In  working  out  their  formula, 
the  Du  Boises  used  a  small  cadaver  of  a  child  21  months  old,  weighing 
6.27  kg.,  with  a  height  of  73.2  cm.,  measured  about  two  hours  after 
death.  They  state  "  the  subject  was  small  for  her  age  and  had  suffered 
from  rachitis;  the  epiphyses  at  the  wrists  were  large  and  the  thorax  was 
pigeon-breasted,  being  narrow  and  very  deep  antero-posteriorly."2 
The  error  in  measurement  by  the  linear  formula  as  compared  with  the 
measurement  of  the  cast  was  —2.9  per  cent.  We  are  of  the  opinion 
that,  in  limiting  the  use  of  their  formula,  weight  rather  than  age  should 
be  the  criterion,  and  that  in  the  case  of  children  the  limit  should  be 
not  children  under  2  years  of  age  but  children  under  6.27  kg.  in  weight. 
With  this  modification  of  their  limit  we  are  hi  full  accord  with  the 
Du  Boises. 

It  seemed  to  us,  however,  that  if  we  computed  the  surface  areas  of 
our  children,  both  by  the  Du  Bois  linear  formula  and  by  some  standard 
formula,  such  as  the  Lissauer  formula,3  we  could  compare  the  values 
obtained  on  these  two  bases  for  children  below  6.27  kg.  in  weight,  note 
the  agreement  between  the  two  methods,  and  thus  estimate  approx- 
imately the  probability  of  accuracy  in  the  linear  formula  for  weights 
below  6  kg.  Exactly  this  procedure  we  have  carried  out.  We  have 
i  carefully  measured  by  the  Du  Bois  linear  formula  the  surface  areas  of 
14  boys  and  19  girls  of  weights  under  6.27  kg.  Comparing  the  areas 
thus  measured  with  the  areas  computed  by  the  formula  proposed  by 
Lissauer  (10.3  %*),  we  found  that  with  our  boys  there  was  a  tendency 
for  the  area  by  the  Lissauer  formula  to  be  slightly  higher  than  that  by 
the  Du  Bois  linear  formula;  therefore,  in  estimating  the  body-surfaces 
of  boys  with  weights  of  6  kg.  or  less,  we  propose  employing  the  formula 
K^tf,  substituting  the  factor  10.0  for  10.3,  in  the  belief  that  10.0 
is  a  more  representative  factor  than  the  10.3  used  by  Lissauer.  This 
new  factor  of  10.0  gives  results  about  3  per  cent  lower  than  the  Lissauer 
factor.  Similarly,  for  estimating  the  body-surfaces  of  girls  below  6  kg. 
in  weight,  the  factor  would  be  more  nearly  10.1  on  the  average,  rather 
than  10.3,  that  is,  1  per  cent  larger  than  the  factor  for  boys.  Accord- 
ingly, for  computing  surface  areas  of  children  with  body-weights  of 
10  kg.  or  less,  the  factor  would  be  not  far  from  that  proposed  by 
Lissauer.  This  agreement  between  the  new  factors  suggested  by 
us  (which  were  obtained  by  inspection  of  the  surfaces  computed  by 

1  Sawyer,  Stone,  and  Du  Bois,  Arch.  Intern.  Med.,  1916,  17,  p.  855. 

2  Sawyer,  Stone,  and  Du  Bois,  loc.  cit,,  p.  856. 

3  Lissauer,  Jahrb.  f.  Kinderheilk.,  1902,  N.  F.,  58,  p.  392. 


58       METABOLISM   AND   GROWTH   FROM   BIRTH   TO   PUBERTY. 


TABLE  13. — Body-girths  of  girls  and  comparison  of  body-surfaces,  as  measured  by  the  Du  Bois 
linear  formula  and  as  computed  from  the  formula  K^w*. 


Sub- 
ject 
No. 

Age. 

Body- 
weight 
(with- 
out 
cloth- 
ing). 

Height. 

Circumference. 

Body-surface. 

At 
nipples. 

At  hips 
and 
but- 
tocks. 

Du  Bois 
linear. 

*$?. 

0) 

Per 

cent  de- 
viation 
from 
Du  Bois 
linear. 

49 
26 
111 
113 
2 
110 
109 
123 
12 
131 
»121 
48 
113 
120 
127 
35 
122 
139 
145 
152 
48 
131 
151 
"143 
160 
134 
140 
122 
113 
123 
139 
131 
135 
165 
152 
139 
160 
35 
»169 
163 
144 
166 
162 
127 
140 
160 

3  wks 

kilos. 
2.84 
3.56 
3.57 
3.65 
3.70 
3.75 
3.78 
3.85 
4.20 
4.34 
4.80 
4.81 
4.88 
4.94 
5.03 
5.07 
5.17 
5.19 
5.22 
5.49 
5.54 
5.55 
5.64 
5.73 
5.90 
6.00 
6.02 
6.03 
6.04 
6.09 
6.11 
6.17 
6.20 
6.24 
6.46 
7.00 
7.05 
7.17 
7.49 
7.63 
7.80 
7.85 
8.00 
8.04 
8.11 
8.12 

cm. 
49.0 
50.0 
53.0 
53.0 
53.0 
51.0 
51.5 
53.5 
53.0 
55.5 
58.0 
56.0 
59.5 
58.0 
57.5 
58.5 
58.5 
63.0 
62.0 
60.5 
61.0 
60.0 
60.0 
59.0 
62.5 
64.0 
60.0 
62.5 
65.0 
63.0 
65.0 
62.0 
63.0 
63.0 
65.0 
67.0 
65.5 
64.5 
67.5 
63.0 
62.0 
68.5 
69.5 
67.0 
68.0 
68.5 

cm. 
«30 

cm. 

227 

sq.  m. 

sg.  m. 

10  days  
13  days 

0.235 

233 
34 
35 
37 
37 
35 

35 
239 
»36 
37 
236 
37 
239 
38 
38 
39 
39 
239 
40 
241 
39 
40 
241 

39 
40 
40 
41 
40 
40 
*39 
42 
41 
43 
41 

241 

41 
243 
47 
45 
244 
46 
46 
44 

»29 
31 

33 

34 

236 

31  wks. 

0.249 

.244 
.252 

.239 
.242 
.244 
.245 
.248 
.263 
.269 
.287 
.287 
.290 
.293 
.296 
.298 
.301 
.302 
.303 
.314 
.316 
.316 
.319 
.323 
.329 
.333 
.334 
.335 
.335 
.338 
.339 
.342 
.344 
.346 
.358 
.388 
.390 
.394 
.406 
.411 
.417 
.419 
.424 
.425 
.428 
.428 

-4.02 

+  1.64 
+6.75 

-2.68 
+  1.72 

-3.22 
-3.51 
-  .33 
+  .32 

+  1.28 

-2.12 
-3.80 

9  days  .  ... 

11  days  
11?  days 

2  mos  1  wk. 

9  days  

3  mos  

233 
36 

35 
236 
39 
35 
36 
38 
233 
39 
233 
37 
37 

41 
40 
39 
38 
40 
40 

'  '.298  ' 
.291 

.311 
.313 
.304 
.313 

.312 

.330 
.342 

.319 
.347 
.335 
.339 
.351 
.336 

2§  mos  
2  mos  
2  mos.  3  j  wks  
5  wks  
2  mos.  1  wk  
4£  mos  
5  mos  .  ... 

3  mos. 

2  mos.  3  wks. 

4  mos.  3  wks  
3  mos.  3|  wks  
4  mos.  3J  wks  
6  mos.  1  wk  
6  mos.  1  wk  
7  mos.  3  wks  
4  mos  
8  mos.  3  wks  
6  mos  
7  mos  

+4.70 
-3.46 
±0.00 
-   .29 
-3.42 
+  1.79 

-5.98 
-1.38 
+  1.31 
+4.00 

-4.02 

-2.34 
+3.20 

+2.66 
-   .70 
+5.16 

40 
40 
43 
39 
*46 
46 
*46 
48 
46 

46 
43 
42 

.368 
.363 
.383 
.375 

10  mos  
4  mos  
9j  mos  

.423 

.427 
.406 

.414 
.431 
.407 

8  mos.  1  wk.  .  . 

4  mos.  3§  wks. 

9  mos  

8  mos  
9|  mos  
1  jr.  2  mos  
1  yr.  3|  wks. 

1  For  values  of  K  see  table  14. 

2  The  measurements  noted  are  not  part  of  the  regular  series  of  Du  Bois  linear  measurements. 

They  are  entered  here  on  the  assumption  that  they  represent  measurements  similar  to 
those  taken  in  the  use  of  the  Du  Bois  linear  formula. 

3  The  data  for  this  subject  were  used  in  plotting  the  charts  shown  in  figures  5  to  14  (pp.  43 

to  68). 


GROWTH. 


59 


TABLE  13. — Body-girths  of  girls  and  comparison  of  body-surfaces,  as  nwasured  by  the  Du  Beds 
linear  formula  and  as  computed  from  the  formula  K^w2 — Continued. 


•T)_  J,r 

Circumference. 

Body-surface. 

GnK 

Jtsoay- 
weight 

Per 

DUD- 

ject 
N_ 

Age. 

(with- 
out 

Height 

At 

At  hips 
and 

DuBois 

K-\/W*. 

cent  de- 
viation 

o. 

cloth- 

nipples 

but- 

linear. 

(i) 

from 

ing). 

tocks. 

Du  Bois 

linear. 

kilos. 

cm. 

cm. 

cm. 

sq.  m. 

sq.  m. 

171 

10  mos  

8.18 

73.5 

44 

46 

0.415 

0.430 

+3.61 

139 

9  mos.  1  wk  

8.26 

70.0 

46 

48 

.416 

.433 

+4.09 

146 

5  mos.  1  wk  

8.30 

68.5 

44 

50 

.425 

.435 

+2.35 

167 

9  mos.  1  wk  

8.52 

69.0 

45 

48 

.458 

.442 

-3.49 

172 

llj  mos.  

8.80 

74.5 

45 

43 

.456 

.452 

-  .88 

166 

1  yr.  1  mo.  1  wk  

8.97 

71.5 

45 

47 

.471 

.458 

-2.76 

127 

1  yr.  3  mos.  3£  wks  

9.02 

73.0 

48 

48 

.475 

.460 

-3.16 

146 

7  mos. 

9.04 

71.0 

44 

48 

.426 

.460 

+7.98 

145 

10  mos   1  wk. 

9.19 

70.0 

46 

48 

.464 

.465 

+  .22 

173 

11^  mos 

9.19 

72.0 

46 

47 

.467 

.465 

—  .43 

171 

1  yr.  2  mos.  Ij  wks  

9.43 

76.5 

45 

47 

.465 

.473 

+  1.72 

144 

7  mos  

9.70 

65.5 

49 

56 

.483 

.482 

-  .21 

139 

1  yr.  2  mos.  3  wks  

9.74 

76.0 

48 

48 

.473 

.483 

+2.11 

122 

1  yr.  4§  mos  

9.80 

76.0 

49 

47 

.495 

.485 

-2.02 

172 

1  yr.  1  mo.  1  wk  

9.84 

77.0 

48 

47 

.503 

.487 

-3.18 

122 

1  yr.  6  mos.  3j  wks  

10.4 

78.5 

47 

50 

.522 

.509 

-2.49 

145 

11  mos.  3|  wks. 

10.5 

73.5 

49 

49 

.514 

.513 

—  .19 

173 

1  yr.  4  mos.  3  wks  

10.5 

78.0 

47 

50 

.520 

.513 

-1.35 

144 

9  mos 

10.6 

67.5 

50 

57  ' 

.520 

.517 

—  .58 

171 

1  yr.  9j  mos  

10.8 

85.5 

49 

47 

.496 

.526 

+6.05 

139 

1  yr.  8?  mos  

10.9 

82.0 

49 

50 

.541 

.530 

-2.03 

174 

2  yrs.  2  wks  

10.9 

79.0 

50 

49 

.536 

.530 

-1.12 

166 

1  yr.  8  mos.  3  wks  

11.0 

80.0 

48 

48 

.518 

.534 

+3.09 

172 

1  yr.  5j  mos  

11.1 

79.5 

49 

49 

.551 

.537 

-2.54 

173 

1  yr.  10  mos.  3  wks  

11.5 

83.0 

48 

51 

.536 

.550 

+2.61 

166 

2  yrs.  2  mos. 

11.8 

85.0 

49 

50 

.568 

.560 

-1.41 

145 

1  yr.  2  mos  

11.8 

76.0 

50 

54 

.562 

.560 

-  .36 

171 

2  yrs.  3  mos  

12.0 

89.5 

49 

49 

.573 

.566 

-1.22 

139 

2  yrs.  2|  mos  

12.3 

88.0 

50 

51 

.588 

.575 

-2.21 

178 

2  yrs.  10  mos.  3j  wks.  .  . 

12.3 

92.0 

50 

49 

.608 

.575 

-5.43 

166 

2  yrs.  9j  mos  

13.2 

88.5 

52 

51 

.599 

.603 

+  .67 

145 

1  yr.  5  mos  

13.4 

80.0 

53 

59 

.621 

.609 

-1.93 

171 

2  yrs.  10  mos.  1^  wks.  .  . 

13.4 

95.0 

51 

51 

.603 

.609 

+1.00 

139 

2  yrs.  6  mos.  3  wks.  .*.  .  . 

13.5 

92.5 

55 

54 

.647 

.612 

-5.41 

166 

3  yrs.  4  mos.  2  wks  

14.0 

92.5 

50 

51 

.604 

.627 

+3.81 

171 

3  yrs.  3  mos.  1  wk  

14.2 

100.0 

51 

50 

.624 

.633 

+  1.44 

179 

3  yrs.  8  mos  

14.5 

98.5 

53 

54 

.654 

.642 

-1.83 

139 

3  yrs.  7  mos.  1  wk  

14.7 

98.0 

53 

55 

.655 

.648 

-1.07 

145 

1  yr.  9  mos.  3  wks  

15.1 

86.5 

55 

60 

.668 

.660 

-1.20 

190 

5  yrs.  3|  mos  

15.2 

103.5 

53 

54 

.691 

.663 

-4.05 

180 

3  yrs.  10  mos.  3  wks.  .  .  . 

15.4 

93.5 

53 

53 

.691 

.669 

-3.18 

183 

4  yrs.  3  mos.  3  wks  

15.7 

97.5 

53 

56 

.654 

.677 

+3.52 

145 

2  yrs.  4  mos  

15.8 

94.0 

53 

56 

.664 

.680 

+2.41 

184 

4  yrs.  4  mos.  1  wk  

16.2 

103.0 

55 

56 

.716 

.692 

-3.35 

181 

3  yrs.  11  mos  16.4 

98.5 

55 

56 

.701 

.697 

-  .57 

171 

4  yrs.  2  mos.  1  wk  16.5 

104.5 

54 

54 

.681 

.700 

+2.79 

195 

6  yrs.  2j  wks.                      '    16.7 

99.5 

55 

56 

.666 

.706 

+6.01 

145 

2  yfs.  9  mos.  3  wks  16.7 

96.5 

55 

58 

.692 

.706 

+2.02 

188 

5  yrs.  1  mo.  1?  wks  

16.9 

103.5 

54 

57 

.736 

.711 

-3.40 

145 

3  yrs.  1  mo.  3  wks  

17.5 

98.5 

55 

58 

.700 

.728 

+4.00 

191 

5  yrs.  5^  mos. 

18.7 

107.5 

57 

58 

.748 

.761 

+1.74 

1  For  values  of  K  see  table  14. 


60   METABOLISM  AND  GEOWTH  FROM  BIRTH  TO  PUBERTY. 


TABLE  13. — Body-girths  of  girls  and  comparison  of  body-surfaces,  as  measured  by  the  Du  Bois 
linear  formula  and  as  computed  from  the  formula  K^lw2 — Continued. 


Sub- 
ject 
No. 

Age. 

Body- 
weight 
(with- 
out 
cloth- 
ing). 

Height. 

Circumference. 

Body-surface. 

At 
nipples. 

At  hips 
and 
but- 
tocks. 

Du  Bois 
linear. 

K-\lwz. 

n 

Per 
cent  de- 
viation 
from 
Du  Bois 
linear. 

206 
*185 
196 
206 
189 
220 
203 
219 
225 
210 
227 
221 
198 
214 
239 
230 
233 
238 
234 
248 
233 
251 
257 
239 

kilos. 
19.2 
19.4 
19.7 
20.6 
22.6 
23.0 
23.1 
23.8 
23.8 
24.0 
24.8 
25.5 
26.0 
26.0 
27.5 
27.6 
27.9 
28.0 
28.2 
28.5 
30.0 
30.8 
36.7 
39.2 

cm. 
113.0 
106.5 
118.0 
116.0 
116.0 
122.0 
119.0 
125.0 
120.5 
122.5 
125.5 
122.0 
124.0 
126.0 
133.5 
133.0 
120.5 
135.5 
133.0 
129.0 
131.0 
138.5 
140.5 
147.5 

cm. 
58 
58 
52 
60 
59 
61 
60 
60 
60 
63 
61 
65 
62 
60 
68 
65 
65 
61 
64 
64 
65 
68 
68 
72 

cm. 
58 
60 
58 
61 
64 
62 
62 
62 
65 
62 
66 
67 
68 
68 
70 
70 
71 
68 
69 
69 
73 
71 
77 
79 

sq.  m. 
0.787 
.775 
.816 
.835 
.871 
.933 
.881 
.890 
.908 
.940 
.939 
1.022 
.966 
.964 
1.089 
1.055 
1.043 
1.047 
1.033 
1.034 
1.065 
1.095 
1.217 
1.272 

sq.  m. 
0.774 
.780 
.788 
.825 
.888 
.898 
.901 
.919 
.919 
.924 
.944 
.962 
.974 
.974 
1.012 
1.014 
1.022 
1.024 
1.029 
1.036 
1.072 
1.090 
1.226 
1.281 

-1.65 

+  .65 
-3.43 
-1.20 
+  1.95 
-3.75 
+2.27 
+3.26 
+  1.21 
-1.70 
+  .53 
-5.87 
+  .83 
+  1.04 
-7.07 
-3.89 
-2.01 
-2.20 
-  .39 
+  .19 
+  .66 
-  .46 
+  -74 
+  .71 

9  yrs.  2  wka  

8  yrs.  11  mos.  1  wk  
9  yrs.  5  mos.  1  wk  

8  yrs.  2  wks  

9  yrs.  8  mos.  3  wks  
9  yrs  

6  yrs.  8  mos  
8  yrs.  2  mos  

11  yrs  

10  yrs.  3  mos  
9  yrs.  2j  mos  :  .  . 
10  yrs.  9  mos.  3?  wks.  .  . 
10  yrs.  5  mos.  3j  wks.  .  . 
11  yrs.  10  mos.  3  wks.  .  . 
10  yrs.  5^  mos  
12  yrs.  2  mos.               .  .    . 

13  yrs.  3  mos.  3  wks  
12  yrs.  3|  wks  

1  For  values  of  K  see  table  14. 

2  The  data  for  this  subject  were  used  in  plotting  the  ^charts 'shown  in  figures  5  to  14  (pp.  43 

to  68). 

the  Du  Bois  and  Lissauer  formulas)  and  the  factor  of  10.3  proposed 
by  Lissauer  rather  strengthens  us  in  our  view  that  the  Du  Bois  linear 
formula  may  be  properly  applied  to  children  weighing  6.27  kg.  or  under. 

Based  upon  our  comparison  of  surface  areas  by  the  Lissauer  and  Du 
Bois  linear  formulas,  we  propose  a  series  of  constants  for  use  in  the 
formula,  the  cube  root  of  the  square  of  the  weight  multiplied  by  a 
constant  factor  K,  which  will  give  the  most  probable  surface  areas  of 
children.  This  constant,  K,  varies  with  children  of  different  weights 
and  there  is  a  slight  difference  between  boys  and  girls,  as  shown  in 
table  14  herewith. 

In  considering  these  constants,  it  will  be  noted  that  for  both  boys 
and  girls  up  to  about  10  or  15  kg.  an  average  factor  of  10.3  would 
not  vary  much  more  than  3  per  cent  from  that  found  best  fitted  to  the 
situation.  Consequently,  we  must  emphasize  strongly  here  the  accu- 
racy of  the  old  Lissauer  formula  for  computing  the  surface  area  of 
young  children.  While  our  own  measurements  of  the  body-surface 


GROWTH. 


61 


of  children  weighing  6  kg.  or  under  would  indicate  that  the  factors 
for  K  are  10.0  and  10.1  for  boys  and  girls,  respectively,  the  Lissauer 
factor  (10.3)  is  still  in  close  agreement  with  our  factors.  This  shows 
the  complete  futility  of  other  constants  formerly  used,  which  were  as 
high  as  11.9,  the  constant  of  Meeh.1 

TABLE  14. — Constants  for  computing  surface  area 


Boys. 

Girls. 

Body-  weight  (without  clothing). 

Constant. 

Body-weight  (without  clothing). 

Constant. 

Up  to    6  kg  

10.0 

Up  to    6  kg  

10.1 

6  to  15  kg  

10.6 

6  to  10  kg  

10.6 

15  to  25  kg  

11.2 

10  to  20  kg  

10.8 

25  to  40  kg  

11.5 

20  to  40  kg  

11.1 

A  close  analysis  of  Lissauer's  data  has  been  given  in  earlier  publica- 
tions from  this  Laboratory.2  The  constants  obtained  from  the  meas- 
urements of  children  by  Lissauer  range  from  8.92  to  12.40;  but  Lis- 
sauer emphasizes  the  fact  that  10  of  his  12  children  were  very  much 
under  weight.  The  factor  finally  selected  by  Lissauer  as  representative 
of  normal  was  a  value  determined  on  a  normal  infant,  S—i.  While 
all  of  our  own  children  were  selected  primarily  from  the  standpoint  of 
normality,  and  while  the  constants  for  children  at  this  early  age,  accord- 
ing to  our  calculations,  more  nearly  approach  the  factor  10.0  or  10.1, 
we  still  believe  that  the  Lissauer  factor  is  on  the  average  very  repre- 
sentative for  children  under  10  kg.  in  weight.  Our  factors  indicate 
strongly  that  there  is  not  a  very  great  disproportion  in  the  surface 
area  with  changes  in  body-weight  under  these  conditions.  In  ex- 
plaining some  of  the  aberrant  types  of  metabolism  frequently  found 
with  atrophic  children,  it  has  been  the  custom  to  lay  considerable 
emphasis  upon  the  fact  that  there  is  a  profound  disturbance  in  the 
relationship  between  body-weight  and  body-surface  with  under- 
weight children.3  Based  upon  our  normal  measurements  and  a 
careful  analysis  of  Lissauer 's  measurements,  we  believe  that  our 
constants  are  the  best  factors  for  computing  the  body-surface  from 
the  body-weight  and  that  a  considerable  degree  of  emaciation  in  all 
probability  does  not  profoundly  affect  the  constant. 

As  an  indication  of  the  accuracy  of  these  computations  of  surface 
area  by  the  revised  Lissauer  formula,  taking  into  account  weight  only 
and  our  several  constants,  we  have  recorded  in  tables  12  and  13  the 
areas  as  computed  by  the  Du  Bois  linear  formula  and  as  computed 
using  our  several  constants.  It  will  be  found  that  with  a  number  of 
our  children,  especially  at  the  lower  weights,  the  Du  Bois  linear 

1  Meeh,  Zeitschr.  f.  Biol.,  1879,  15,  p.  425. 

2  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914,  p.  164;    see  also  Harris  and 

Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  143. 
'Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914,  p.  163. 


62   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


measurements  are  lacking.  We  believe,  however,  from  our  com- 
parison of  the  areas  by  the  two  methods  for  the  14  boys  and  19  girls 
under  6.27  kg.  in  weight,  that  for  children  at  this  lower  weight-range 
the  use  of  our  constants  gives  the  areas  with  a  high  degree  of  probability 
In  the  last  column  of  the  tables  is  indicated  the  percentage  difference 
between  the  body-surface  by  the  Du  Bois  linear  formula  as  the  base- 
line, and  that  computed  by  our  constants.  In  examining  the 
tables,  it  is  important  to  note  that  the  value  of  K  changes  with  the 
sex  and  with  the  various  weights,  as  indicated  in  table  14  given 
above. 

From  tables  12  and  13  it  can  be  seen  that  the  elaborate  series  of 
Du  Bois  measurements  are  no  longer  necessary  in  computing  the  sur- 
face areas  of  children — certainly  not  children  approximating  normal 
form — but  one  can  compute  the  area,  using  the  factors  as  given  in 
table  14.  For  the  sake  of  convenience  we  have  felt  it  desirable  to 
give  a  table  for  boys  and  girls  separately,  showing  the  surface  areas 
based  upon  our  several  factors  for  each  increasing  kilogram  in  weight 
from  3  kg.  to  40  kg.  From  this  table  the  interpolations  for  fractions 
of  kilograms  are  readily  obtained.  While  by  no  means  certain  of  the 
importance  of  the  surface  area,  particularly  in  relation  to  metabolism 
measurements,  we  still  deem  it  desirable  to  have  a  tabular  method 
for  securing  rapidly  the  body-surface  of  children  based  upon  the 
admirable  linear  formula  of  Du  Bois.  These  surface  areas,  as  pre- 
sented in  table  15,  are  primarily  of  significance  as  purely  physical 
measurements. 

TABLE  15. — Estimated  body-surfaces  for  body-weights  from  8  to  40  kilograms. 


Body- 

Body- 

Body- 

weight 

Surface1 

Surface1 

weight 

Surface1 

Surface1 

weight 

Surface1 

Surface1 

(with- 

esti- 

esti- 

(with- 

esti- 

esti- 

(with- 

esti- 

esti- 

out 

mated 

mated 

out 

mated 

mated 

out 

mated 

mated 

cloth- 

for boys. 

for  girls. 

cloth- 

for boys. 

for  girls. 

cloth- 

for boys. 

for  girls. 

ing). 

ing). 

ing). 

kilos. 

sq.  m. 

89.  m. 

kilos. 

sq.  m. 

sq.  m. 

kilos. 

sq.  m. 

sq.  m. 

3 

0.208 

0.210 

16 

0.711 

0.686 

29 

1.086 

1.048 

4 

.252 

.255 

17 

.740 

.714 

30 

1.110 

1.072 

5 

.292 

.295 

18 

.769 

.742 

31 

1.134 

1.095 

6 

.330 

.333 

19 

.797 

.769 

32 

1.159 

1.119 

7 

.388 

.388 

20 

.825 

.796 

33 

1.183 

1.142 

8 

.424 

.424 

21 

.853 

.845 

34 

1.207 

1.164 

9 

.459 

.459 

22 

.879 

.872 

35 

1.230 

1.188 

10 

.492 

.492 

23 

.906 

.898 

36 

1.254 

1.210 

11 

.524 

.534 

24 

.932 

.924 

37 

1.277 

1.233 

12 

.556 

.566 

25 

.958 

.949 

38 

1.300 

1.255 

13 

.586 

.597 

26 

1.009 

.974 

39 

1.323 

1.277 

14 

.616 

.627 

27 

1.035 

.999 

40 

1.345 

1.298 

15 

.645 

.657 

28 

1.060 

1.024 

1  Surfaces  estimated,  using  formula 
table  14. 


for  values  of  K  at  the  different  weight-ranges,  see 


GROWTH.  63 

PHYSIOLOGICAL  AND  ANTHROPOMETRICAL  SIGNIFICANCE  OF  SURFACE  AREA. 

Studies  of  the  body-surface  measurements  of  children  have  been 
prompted  primarily  from  an  attempt  to  correlate  the  total  heat  pro- 
duction of  children  with  some  physical  factor.  The  apparent  dis- 
crepancy between  the  heat  production  per  kilogram  of  body-weight 
and  the  total  weight  of  the  child  at  various  ages  early  led  to  an  effort 
to  secure,  if  possible,  a  uniform  basis  for  comparison  of  children  and 
adults,  i.e.,  individuals  of  greatly  differing  weights,  and  it  was  believed 
that  the  heat  production  per  unit  of  body-surface  was  much  more 
nearly  constant  than  the  heat  production  based  either  upon  the 
body-weight  or  any  other  factor;  in  fact,  so  constant  as  to  represent  a 
"physiological  law."  The  extensive  series  of  body-surface  measure- 
ments made  by  us  were  admittedly  secured  primarily  in  connection 
with  a  study  of  the  possible  relationship  between  heat  production  and 
body-weight  on  the  one  hand  and  heat  production  and  body-surface 
on  the  other.  A  recent  critical  analysis  of  the  so-called  "  body-surface 
law"  appearing  from  this  laboratory1  vitiates,  we  believe,  to  a  very 
large  degree,  the  significance  of  this  "law,"  particularly  that  part  of  it 
which  recognizes  a  causal  relationship  between  the  surface  area  and 
the  heat  production.  Our  present  position  on  this  point  can  be  no 
better  set  forth  than  by  repetition  of  an  opinion  expressed  six  years 
ago2  to  the  effect  that  we  believe  body-surface  has  no  significance  in 
connection  with  heat  production,  except  that  it  represents  a  general 
morphological  law  of  growth. 

We  have,  however,  a  series  of  carefully  measured  surface  areas  of 
children  of  varying  ages.  That  these  measurements  are  of  direct 
physiological  and  anthropometrical  importance  is  undoubtedly  true. 
Thus,  the  marked  changes  appearing  in  the  general  configuration  of 
the  growing  child  as  compared  with  the  adult  are  familiar  to  all. 
Are  these  changes  accompanied  by  disturbances  in  the  general  rela- 
tionship between  surface  area  and  body-weight,  or  surface  area  and 
height,  or  surface  area  and  age?  This  question  can  be  adequately 
answered  only  by  graphic  presentation  of  our  data. 

RELATIONSHIP  BETWEEN  SURFACE  AREA  AND  BODY-WEIGHT,  HEIGHT,  AND  AGE  WITH  BOYS. 

Since  these  surface  areas  are  all  actually  measured  according  to  the 
Du  Bois  linear  formula  and  are  not  computed  from  the  body-weight, 
it  seems  perfectly  justifiable  to  plot  them  against  age,  height,  and 
body-weight,  and  this  we  have  done  in  the  six  following  charts  for 
both  boys  and  girls.3  Thus,  in  figure  9  we  have  plotted  the  body- 

1  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  129. 

z  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914,  p.  168. 

»  See  tables  26,  27,  and  28  (pp.  112,  116,  and  120)  and  tables  12  and  13  (pp.  54  and  58)  for  data 
plotted  on  these  charts.  It  will  be  noted  that  in  20  instances  with  the  very  young  boys  and 
in  19  instances  with  the  very  young  girls  the  surface  areas  have  been  computed  from  the 
Lissauer  formula,  since  the  Du  Bois  measurements  were  not  made  in  these  cases.  We  feel 
justified  in  plotting  these  values  on  our  charts,  however,  since  we  have  demonstrated  the 
remarkably  close  agreement  between  the  surface-area  measurements  obtained  by  the 
Lissauer  formula  and  the  Du  Bois  linear  formula  for  young  children. 


64   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

surface  referred  to  weight  for  our  boy  subjects.  This  curve,  which 
represents  the  impressions  of  five  members  of  the  Laboratory  staff, 
shows  that  hi  general  the  relationship  between  the  surface  area  and 
weight  is  almost  a  linear  one,  particularly  after  the  8-kg.  weight.  In- 
deed, it  can  be  seen  that  a  straight-line  curve  would  at  the  higher 


Sq.m. 


BODY  SURFACE    REFERRED  TO  WEIGHT. 


i'Aj 

x^ 

^* 

*  * 

^ 

*\    . 

x 

/ 

'/^' 

X 

^ 

i 

..3 

X 

x 

/? 

> 

x 

X 

X 

•f 

^ 

S 

/ 

/ 

,A 

kgs.4       e 

8       10      12      14       16       18      20     22     24      26      28     30     32     34     36      38     40     4 

FIG.  9. — Relationship  between  body-surface  and  body-weight  with  boys. 

weight-levels  fit  as  well  as  any  more  complicated  order  of  curve.  The 
correlation  between  the  body-surface  and  weight  is  strikingly  shown 
hi  this  chart.  The  widest  difference  for  a  given  weight  is  found  at 
about  the  weight  of  30  kg.,  namely,  a  difference  of  about  0.13  square 
meter  or  a  maximum  difference  of  about  12  per  cent.  So  far  as  rela- 
tionship between  body-weight  and  body-surface  with  boys  is  con- 
cerned, therefore,  it  is  clear  that  there  are  no  abnormal  fluctuations 
in  the  curve  at  any  point  throughout  youthful  life,  and  if  there  are 
marked  changes  in  the  configuration  of  the  body,  these  must  involve 
weight  as  well  as  surface. 

In  figure  10  we  have  plotted  the  measured  body-surface  against  the 
height  of  our  boys.  Here,  although  the  curve  representing  the  general 
trend  of  the  relationship  is  not  a  straight  line,  nevertheless  it  is  reason- 
ably regular  throughout  the  entire  age-range  studied.  The  deviations 
either  side  of  the  curve  are  somewhat  greater  than  those  found  in  the 
relationship  between  body-surface  and  weight,  but  there  is  nothing  to 


GROWTH. 


65 


indicate  an  especially  abnormal  disturbance  in  the  relationship  between 
body-surface  and  height,  although  obviously  there  is  not  so  close  a 
correlation  between  height  and  body-surface  as  was  found  between 
weight  and  body-surface.  Knowing  the  general  correlation  between 
weight  and  height,  we  may  therefore  infer  that  if  there  are  gross 
changes  in  configuration  with  boys  in  this  age-range,  judged  from  the 
adult  standpoint,  they  are  not  such  as  to  disturb  materially  the 
relationship  between  surface  area  and  weight  or  surface  area  and  height. 


So-m. 


BODY  SURFACE    REFERRED  TO  HEIGHT. 


BOYS. 


/ 

X 

•  • 

X 

X- 

X 

.   * 

y 

X 

jr' 

£X 

,>• 

•' 

^ 

^ 

^> 

^ 

—^ 

^ 

•^ 

,'. 

X* 

#. 

s* 

*^1 

ins.             60               70                80                90               1OO              1 

0              1! 

20              130              140              1! 

)0             16 

FIG.  10. — Relationship  ^between  body-surface  and  height  with  boys. 

Although  from  the  well-known  correlation  between  height,  weight, 
and  age  of  children  of  this  age-range,  one  would  a  priori  expect  a 
reasonably  close  correlation  between  body-surface  and  age,  we  have 
plotted  these  factors  in  figure  11  for  our  boys.  As  has  already  been 
noted,  there  is  very  considerable  regularity  in  the  relationship  between 
body-surface  and  height  and  body-surface  and  weight,  but,  contrary 
to  our  expectations,  in  the  relationship  between  body-surface  and  age 
we  note  rather  striking  differences,  and  a  straight-line  curve  will 
hardly  suffice  here  to  indicate  the  general  relationship,  particularly 
at  the  youngest  ages.  Beyond  the  age  of  2  years  the  curve  is  reason- 
ably regular  in  form,  but  there  are  wide  deviations  either  side  at  the 
higher  age-ranges.  We  thus  see  that  with  boys  there  is  a  closer  corre- 
lation between  body-surface  and  weight  or  height  than  between  body- 
surface  and  age.  As  evidence  for  the  rather  considerable  changes  in 


66   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

surface  area  that  may  actually  occur  in  children  of  the  same  age,  these 
points  are  of  interest,  although  it  is  clear  that  age  itself  is  not  an 
accurate  index  of  surface  area,  any  more  than  it  is  an  accurate  index 
of  height  or  weight. 


Sq.  m.                                  BODY   SURFACE  REFERRED  TO  AGE.                                   BOYS. 

1.4 
1.3 
1.2 
1.1 
10 

/ 

. 

/ 

.-. 

/. 

/• 

'/. 

S" 

.9 
.8 

.6 
.5 
.4 
.3 
2 

.. 

^ 

•  . 

" 

. 

/. 

J/'. 

• 

/ 

/s 

/ 

. 

'^ 

'V 

$ 

t 

.1 

FIG.  11. — Relationship  between  body-surface  and  age  with  boys. 

RELATIONSHIP  BETWEEN  SURFACE   AREA  AND   BODY-WEIGHT,   HEIGHT,   AND  AGE 
WITH   GIRLS. 

In  figures  12,  13,  and  14  we  have  plotted  the  relationships  between 
body-surface  and  body-weight,  body-surface  and  height,  and  body- 
surface  and  age  for  our  girl  subjects.  The  picture  in  all  three  instances 
is  strikingly  similar  to  that  found  for  boys.  The  relationship  between 
body-surface  and  weight  is  closely  approximated  by  a  straight  line, 
although  a  slightly  smoothed  curve,  as  sketched  on  the  chart,  fits  the 
situation  somewhat  better.  No  pronounced  bend  in  this  line  is  to  be 
noted  at  any  particular  weight.  The  body-surface  is  not  so  closely 
correlated  to  height  as  to  weight,  as  is  seen  by  the  somewhat  wider 
scattering  of  the  points  about  the  curve  sketched  on  figure  13.  Thus, 
while  girls  of  the  same  weight  have  essentially  similar  surface  areas, 
girls  of  the  same  height  may  vary  rather  considerably  in  surface  area. 
Perhaps  the  widest  difference  is  noted  with  the  two  girls  having  heights 
of  85.5  cm.  and  86.5  cm.  Here  the  difference  in  height  is  but  1  cm., 


GROWTH. 


67 


and  yet  there  is  a  difference  of  almost  0.2  sq.  m.  in  surface  area. 
Finally,  in  the  relationship  between  surface  area  and  age  with  girls, 
as  exhibited  in  the  scatter  diagram  in  figure  14,  we  note  very  wide 


Sq.m 
1.3 


BODY  SURFACE   REFERRED  TO  WEIGHT. 


2kgs.4         6        8        10      12      14       16      18      20     22     24     26      28     30     32      34      36      38     40 

FIG.  12. — Relationship  between  body-surface  and  body-weight  with  girls. 

™-  BODY  SURFACE  REFERRED  TO  HEIGHT.  GIRLS. 


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Cms.    50  60  70  80  90  100  110  120  130  140 

FIG.  13. — Relationship  between  body-surface  and  height  with  girls. 

deviations  from  the  general  trend,  quite  similar  to  those  found  with 
boys,  indicating  again  that  the  relationship  between  age  and  body- 
surface  is  by  no  means  a  close  one.  This  irregularity  in  relationship 


68   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

is  in  large  part  due,  we  believe,  to  the  fact  that  children  of  different 
ages  may  have  markedly  different  weights,  while  children  of  the  same 
weight  will  have  essentially  the  same  surface  area,  and  children  of 
the  same  height  nearly  the  same  surface  area.  At  no  point  in  figures 
12,  13,  or  14  is  there  any  noticeable  deviation  in  the  line  that  would 
indicate  a  profound  disturbance  In  the  relationship  of  body-surface 
to  either  height,  weight,  or  age. 


Sq.  m. 


BODY  SURFACE  REFERRED  TO  AGE. 


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5        6        7        8        9       10      11       12      13      14 

FIG.  14.— Relationship  between  body-surface  and  age  with  girls. 

Although  a  further  detailed  analysis  is  out  of  place  here,  it  is  im- 
portant that  these  surface  areas,  as  actually  measured,  should  be 
permanently  recorded.  From  these  charts  the  reader  may  readily 
pick  out  the  individuals  deviating  farthest  from  the  general  line  show- 
ing the  relationships  between  body-surface  and  age,  weight,  or  height, 
and  compare  them  with  our  list  of  subjects  in  tables  12,  13,  27,  and  28, 
where  all  the  anthropometric  data  are  given.  It  was  impossible  to 
indicate  the  subjects'  numbers  on  these  charts  without  making  the 
charts  altogether  too  confusing. 

Owing  to  the  earlier  concept  of  an  intimate  causal  relationship 
between  body-surface  and  metabolism,  it  is  important  to  use  these 
carefully  measured  surface  areas  not  only  in  reference  to  body-weight, 
height,  and  age,  but  likewise  for  comparison  with  the  measured  meta- 
bolism. This  latter  comparison  is  accorded  treatment  in  the  subse- 
quent chapters  of  this  report. 


NORMAL,    AVERAGE,    AND    IDEAL   STATES   OF   NUTRITION.      69 

NORMAL,  AVERAGE,  AND  IDEAL  STATES  OF  NUTRITION. 

It  has  long  been  recognized  that  body-weight  alone  referred  to  age 
may  not  be  considered  an  ideal  indication  of  the  normality  of  the 
child's  state  of  nutrition.  Many  investigators,  in  attempting  to 
secure  an  index  of  nutritional  state,  have  considered  height  as  well  as 
weight,  both  in  reference  to  age,  and  others  have  added  the  girth  of 
some  part  of  the  body  or  some  power  of  the  length.  One  of  the  most 
recent  formulas  is  that  suggested  by  Van  der  Loo,1  who  states  that 
"as  children  grow  taller  they  increase  more  proportionately  in  weight 
than  in  length,  so  that  the  weight  divided  by  the  square  of  the  length 
gives  a  fairly  good  index  for  comparison  of  conditions  in  different 
children  or  in  the  same  child  at  different  tunes."  For  practical 
purposes  it  would  be  almost  impossible  to  make  direct  Du  Bois  meas- 
urements and  establish  the  relationship  between  surface  area  and 
any  of  the  other  physical  factors  as  an  index  of  normality  of  nutrition, 
although  we  have  given  tables  (tables  14  and  15)  whereby  the  surface 
area  can  be  very  closely  approximated  by  computation  based  upon 
several  constants. 

Normal  height. — From  our  earlier  discussion  it  seems  quite  clear 
that  we  must  consider  the  normal  condition  of  the  child  from  several 
bases.  In  the  first  place,  what  is  the  normal  height  of  the  child? 
With  adults  there  is  no  such  thing  as  normal  height.  The  ranges  of 
height  with  men  and  with  women  are  very  extended  indeed.  We 
form  definite  opinions  as  to  whether  a  man  is  especially  short  or 
especially  tall,  but  no  one  would  care  to  state  the  normal  height  for 
man.  The  average  height  for  a  man  is  commonly  given  as  170  cm., 
but  it  is  granted  that  there  are  very  wide  variations  from  this  average 
height.  With  adults,  then,  the  difference  between  normal  and  average 
is  clearly  recognized,  but  the  average  is  taken  as  normal.  Thus,  the 
heights  of  a  large  group  of  individuals  representing  the  general  run 
of  the  population  are  measured  and  averaged,  and  this  average  value 
is  considered  as  the  normal  value.  We  contend  that  this  procedure 
is  entirely  erroneous  when  applied  to  children,  although  it  is  regularly 
employed  and  is  a  basis  of  most  of  the  tables  and  charts  in  current  use. 

With  children  there  should  be,  or  at  least  there  is  properly  supposed 
to  be,  a  reasonably  definite  height  for  an  age.  It  has  been  stated 
earlier  in  our  discussion  that  age,  weight,  and  height  are  rather  closely 
correlated  with  children,  in  contradistinction  to  the  situation  with 
adults.  As  children  grow  older  they  increase  in  height  and  weight 
approximately  in  the  same  degree.  It  has  been  repeatedly  shown  that 
racial  characteristics  appear  very  prominently  in  height.  Our  Ameri- 
can population  is  by  no  means  of  a  pure  strain,  and  a  group  of  children 

1  Van  der  Loo,  Nederl.  Tijdschr.  v.  Geneeak.,  Amst.,  1919,  1,  p.  447;  cited  in  Journ.  Am.  Mod. 
Assoc.,  1919,  72,  p.  1403. 


70   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

from  a  large  public  school,  especially  in  our  big  cities,  may  represent  a 
large  percentage  of  foreign  blood.  Under  these  conditions  an  average 
figure  may  certainly  be  obtained,  but  we  believe  it  is  not  justifiable 
to  consider  this  average  figure  as  normal.  From  the  consideration  of 
the  charts  in  which  our  private-school  data  were  plotted  (figs.  4  and  6), 
it  is  clear  that  the  private-school  children  on  the  whole  are  considerably 
taller  for  their  age  than  are  our  laboratory  children,  or,  indeed,  the 
extensive  series  we  quote  from  other  writers.  In  other  words,  it 
seems  evident  that  the  conditions  obtaining  with  the  children  of  private 
schools  in  eastern  Massachusetts  produce  a  greater  skeletal  growth,  as 
indicated  by  the  height.  On  this  basis,  all  of  these  private-school 
children  are  supernormal;  in  other  words,  they  are  certainly  above 
the  average,  and  the  question  immediately  arises,  "Is  the  average  to 
be  considered  as  normal?  " 

If  one  objects  to  the  values  found  with  the  private-school  children 
as  normal  values,  no  exception  can  be  taken  to  the  expression  "  ideal 
value."  Hence  one  should  compare  the  height  and  weight  of  a  child 
not  with  the  average  or  the  fictitious  normal,  but  with  the  ideal,  which 
is  unquestionably  represented  more  nearly  by  our  data  from  private 
schools.  We  wish  here  especially  to  emphasize  the  difference  between 
average,  normal,  and  ideal.  When  a  child  is  short  for  his  age  this 
instantly  indicates  one  of  two  things.  In  the  first  place,  the  child 
may  be  the  offspring  of  a  race  of  people  or  of  parents  of  normally 
short  stature;  secondly,  there  may  be  a  serious  deficiency  in  the 
growth-producing  factors  in  the  diet.  This  deficiency  in  growth- 
producing  factors  is  to  be  sharply  distinguished  from  the  caloric  con- 
tent of  the  diet,  for  it  has  been  shown,  with  animals  at  least,  that  when 
they  are  maintained  upon  a  diet  of  constant  caloric  value  during  the 
active  period  of  growth,  skeletal  growth  is  made  at  the  expense  of  the 
addition  of  tissue. 

We  should  no  longer,  then,  compare  the  height  of  our  children  to  the 
average  and  call  this  normal.  The  fact  that  a  group  of  800  private- 
school  children  may  attain  a  height  for  age  considerably  above  that 
of  the  average  or  so-called  "normal"  can  be  taken  only  as  an  index  of 
the  fact  that  this  average  represents  children  living  under  conditions 
which  do  not  produce  the  best  growth.  In  any  educational  campaign 
for  the  promotion  of  child  welfare  it  is  important  to  lay  special  stress 
upon  those  conditions  favoring  the  largest  skeletal  growth.  Conse- 
quently we  believe  that  all  previous  charts  indicating  height  for  age 
are  not  ideal  and  represent  simply  a  group  of  the  population  that  has 
been  stunted,  in  part  at  least,  by  abnormal  living  conditions  and 
perhaps  deficient  dietary  constituents.  In  laying  down  this  thesis  we 
are,  of  course,  open  to  the  criticisms  that  our  private-school  children 
were  less  contaminated  by  racial  commingling  and  that  the  shorter 
statured  people  did  not  send  their  children  to  these  private  schools — 


NORMAL,    AVERAGE,    AND    IDEAL   STATES   OF   NUTRITION.      71 

in  other  words,  that  our  private-school  children  represent  the  more 
purely  typical  American  or  Anglo-Saxon  type.  To  a  certain  extent 
this  is  probably  true,  but  we  are  not  in  a  position  to  throw  definite 
light  upon  this  subject.  We  think  it  highly  improbable,  however, 
that  this  explanation  completely  accounts  for  the  greater  height  of 
this  group  of  children.  For  an  estimate  of  the  ideal  height  of  children 
we  believe,  therefore,  that  one  should  rely  not  upon  the  so-called 
"normal"  curve,  but  more  nearly  upon  an  ideal  curve  which  is  measur- 
ably higher  than  a  normal  or  average  commonly  given.  On  this 
basis  many  analyses  of  the  measurements  of  children  which  indicate 
that  the  children  are  above  normal  height  simply  mean  that  the 
normal  level  is  arbitrarily  adjusted  at  too  low  a  point.  Nutrition 
experts  and  pediatricians  must  hold  this  important  relationship  clearly 
in  mind  and  not  be  content  with  the  statement  that  a  child  is  of 
average  height  when  the  possibilities  of  greater  skeletal  growth  are 
presented  by  better  living  conditions,  medical  treatment,  and  general 
care. 

Normal  body-weight. — The  emphasis  laid  upon  the  relationship 
between  height  and  age  is  far  overshadowed  by  that  laid  upon  the 
relationship  between  body-weight  and  age.  A  child  of  a  certain  age 
is  commonly  supposed  to  have  a  certain  weight,  and  if  below  this 
weight  is  considered  an  underweight  child.  As  in  the  case  of  height, 
average  weight  is  invariably  taken  as  the  normal  weight.  Normal 
tables  or  average  tables  have  been  prepared,  and  almost  every  writer 
combines  several  of  the  earlier  series  and  obtains  his  own  individual 
normal  which  he  uses  for  his  study.  The  very  fact  that  this  divergence 
and  uncertainty  exist  in  the  minds  of  all  students  of  the  physiology  of 
childhood  shows  that  there  has  been  an  unwritten  hesitation  to  accept 
as  normal  many  of  these  values.  We  believe  that  with  children 
certainly  we  should  no  longer  consider  the  average  as  normal.  With 
adults  there  are  a  large  number  of  overweight  individuals  to  compensate 
for  the  number  of  underweight  individuals,  so  that  the  average  value 
for  body-weight  represents  a  median  line  with  approximately  the  same 
proportion  of  overweights  as  underweights.  With  children  the  situa- 
tion is  quite  the  reverse.  The  number  of  overweight  children,  even 
using  the  erroneous  term  " normal"  when  applied  to  the  average, 
are  much  fewer  than  the  number  of  underweights.  On  standing  in 
front  of  any  of  our  public  schools  and  noting  the  condition  of  the 
children  running  out  at  the  end  of  a  day's  session,  one  may  see  at  a 
glance  that  the  obviously  overweight  children  are  very  few  indeed, 
while  those  who  are  obviously  underweight  usually  pass  by  more 
rapidly  than  they  can  be  counted.  On  this  ground,  therefore,  to  take 
an  average  value  for  children  seems  wholly  erroneous. 

If  a  child  is  seemingly  underweight  for  a  given  age,  this  may  be 
due  in  part  to  his  short  stature — possibly  a  racial  characteristic — 


72   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

or  may  be  due  to  a  deficiency  in  the  growth-promoting  factors  in  the 
diet.  In  other  words,  underweight  may  be  simply  a  concurrent  factor 
with  short  stature,  or,  if  the  height  is  up  to  the  average  and  the  child 
is  still  noticeably  underweight,  this  condition  may  be  due  distinctly 
to  an  insufficient  caloric  intake.  This  latter  is  the  more  probable  and 
more  common  situation.  If  we  refer  again  to  our  data  for  private- 
school  children,  we  will  recall  that  at  all  ages  they  were  measurably 
heavier  for  their  age  than  were  the  other  normal  series  that  we  have 
reported,  both  our  own  laboratory  series  and  the  earlier  standard  series. 
As  we  pointed  out,  however,  their  greater  weight  is  in  large  part  due 
to  their  greater  height.  Still,  the  fact  that  outdoor  environment, 
better  medical  attention,  and  probably  better  dietetic  conditions  have 
produced  a  larger  and  better  conditioned  child  than  the  ordinary, 
especially  in  our  public  schools,  is  a  factor  that  must  not  be  overlooked. 
So-called  "normal  weight"  is  not  normal,  but  is  merely  average. 
We  believe  that  our  ideal  figures,  as  represented  hi  our  curves  for 
private-school  children,  more  truly  represent  the  normal  and  that 
pediatricians  should  strive  for  the  higher  weight  for  age  as  exhibited 
by  our  private-school  children  rather  than  for  the  average  weight  for 
age,  although  here  again  we  clearly  recognize  the  differences  in  nation- 
ality hi  mixed  groups,  such  as  those  being  studied  in  any  of  the  public 
schools,  and  the  probably  purer  strain  of  nationality  in  our  private 
schools. 

BODY-WEIGHT  IN  RELATION  TO  HEIGHT  AS  AN   INDEX  OF 
STATE  OF  NUTRITION. 

From  the  foregoing  discussion  it  is  obvious  that  an  index  of  the  state 
of  nutrition  based  on  the  relationships  of  height  to  age  and  weight 
to  age  is  subject  to  very  considerable  error,  because  although  a  child 
may  be  of  normally  short  stature  with  an  accompanying  small  body- 
weight,  due  to  racial  characteristics,  on  the  basis  of  age  he  would  be 
considered  to  be  both  underheight  and  underweight.  If  the  short 
stature  is  due  to  racial  characteristics  and  not  to  deficiency  in  the 
growth-promoting  factors  in  the  diet,  the  child  may  still  be  considered 
normal,  indeed  may  be  considered  ideal.  Before  this  condition  can  be 
established,  however,  a  far  greater  study  of  the  height-weight  ratio 
of  children  of  normally  short  parents  should  be  made,  and  in  con- 
sidering the  average  mixed  population  of  American  schools  the  element 
of  racial  characteristics  must  not  be  overlooked. 

Having  shown  that  neither  an  average  height  for  age  nor  an  average 
weight  for  age  is  best  suited  for  an  index  of  nutritional  state,  since 
the  height  may  be  accompanied  by  varying  weights  and  vice  versa, 
it  is  clear  that  as  an  index  of  the  best  proportional  distribution  of 
flesh  to  skeleton  the  relationship  between  height  and  weight  is  most 
satisfactory.  For  a  child  of  a  given  height  a  definite  weight  is  pro- 


NORMAL,    AVERAGE,    AND   IDEAL   STATES   OF   NUTRITION.      73 

ductive  of  a  fullness  of  development  and  addition  of  flesh  that  may 
be  termed  ideal.  When  the  child  has  too  little  flesh  it  is  very  obvious, 
and  likewise  when  it  has  too  much  flesh.  The  problem  then  arises  as 
to  what  is  the  best  proportion  between  weight  and  height  for  children. 
Should  children  be  somewhat  light  in  build  or  distinctly  overweight, 
as  judged  by  the  popular  conception  of  underweight  and  overweight 
when  applied  to  children?  Referring  again  to  our  private-school 
data,  we  find  that  although  these  children  are  heavier  and  taller  than 
other  series  of  normal  children  at  the  same  age,  when  the  height 
and  weight  are  compared  they  are  on  the  whole  somewhat  thinner 
for  their  height  than  are  our  normal  laboratory  children  selected  for 
this  study.  On  the  basis  only  of  weight  referred  to  height,  therefore, 
it  would  appear  as  if  our  laboratory  children  had  somewhat  the 
advantage  over  the  group  of  private-school  children,  i.  e.,  so  far  as 
proportion  is  concerned.  It  still  remains  a  fact,  however,  that  had 
our  laboratory  children  been  given  the  advantages  of  private-school 
children,  namely,  outdoor  life,  better  medical  care,  operative  treat- 
ment if  needed,  and  better  diet,  particularly  with  regard  to  growth- 
promoting  factors,  the  skeletal  growth  would  probably  have  been 
greater  than  actually  noted. 

The  question  is  a  serious  one,  then,  as  to  whether  we  should  con- 
sider a  child  of  a  certain  age  who  has  a  large  proportion  of  flesh  for 
his  height  a  better  nourished  child  than  one  of  the  same  age  who  is 
taller  and  at  the  same  time  heavier,  but  in  whom  the  proportion 
between  weight  and  height  is  not  so  great  as  with  the  shorter  child. 
This  question  leads  us  to  a  consideration  of  the  importance  of  the  diet 
factors  which  play  a  role  in  growth.  No  one  would  seek  for  abnormal 
rapidity  in  the  growth  of  children.  In  the  normal  development  of  the 
child  growth  proceeds  with  a  considerable  degree  of  regularity  and, 
on  the  average,  at  a  certain  rate  of  rapidity.  When  children,  however, 
are  subjected  to  ideal  outdoor  life,  with  plenty  of  food  and  excellent 
medical  care,  they  do  grow — in  skeletal  form,  at  least,  as  well  as  in 
total  weight — at  a  somewhat  greater  rate  than  otherwise.  Is  this 
desirable  or  not?  Everything  points  to  the  desirability  of  this  condi- 
tion, and  yet  on  close  analysis  it  is  seen  that  these  private-school 
children  do  not  have  the  proportion  of  weight  to  height  found  with  the 
group  of  laboratory  children  selected  for  our  measurements.  Which, 
therefore,  of  the  two  factors  is  the  most  important  in  the  process  of 
growth,  height  or  weight?  The  striking  difference  between  the 
private-school  children  and  our  laboratory  children  is  the  greater 
height  and  correspondingly  greater  weight  of  the  former,  although  the 
weight  is  in  all  probability  simply  a  natural  concomitant  of  the  height. 
The  fact  that  the  obviously  ideal  conditions  of  private-school  life 
result  in  this  increased  growth  would  seem  to  be  prima  fade  evidence 
of  its  desirability.  On  the  other  hand,  we  must  consider  for  a  moment 


74   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

the  relationship  between  weight  and  height  which  has  resulted,  with 
our  laboratory  children  at  least,  in  a  better  proportionment — that  is, 
these  children  are  somewhat  heavier  for  a  given  height  than  are  the 
private-school  children. 

The  underweight  child  is  a  great  care  to  nutritional  experts,  and  so 
the  greatest  stress  is  laid  upon  the  question  of  underweight,  and  appar- 
ently little,  if  any,  attention  is  given  to  underheight.  We  have 
pointed  out  that  underheight  may  be  due  to  erroneous  dietary  condi- 
tions, although  in  many  instances  such  conditions  are  perhaps  entirely 
unsuspected.  But  the  chief  attention  of  all  dietitians  and  pedi- 
atricians is  given  to  the  underweight  of  the  child;  hence,  the  stress 
laid  upon  the  larger  proportion  of  weight  for  height.  The  desirability 
of  advocating  this  proportion  is  well  substantiated  by  the  importance 
ascribed  to  the  relationship  between  weight  and  height  in  the  best  and 
recent  studies  of  vital  statistics.  These  statistics  show  clearly  that 
longevity  is  better  favored  in  youthful  adults,  particularly  under  30 
years  of  age,  if  there  is  a  certain  degree  of  overweight;  that  is,  that 
those  youths  over  the  average  weight  usually  have  a  somewhat  better 
expectancy  of  life.  Beyond  the  age  of  35  years  statistics  show  that  a 
weight  somewhat  under  the  average  insures  a  better  life  expectancy. 
If  during  the  period  of  early  adult  age,  longevity  is  favored  by  having 
the  weight  somewhat  above  the  average,  it  seems  a  reasonable  con- 
clusion that  this  same  condition  must  be  advantageous  for  children. 
Consequently  we  believe  that  during  the  entire  period  of  growth  the 
weight  should,  if  possible,  be  somewhat  over  the  average  and  should 
approach  the  ideal  as  indicated  by  the  weight  for  ages  of  our  private- 
school  children.  Indeed,  it  seems  logical  to  assume  that  if  the  private- 
school  children  had  been  supplied  with  a  larger  amount  of  food,  so 
that  they  could  have  put  on  more  flesh  and  had  a  proportion  of  weight 
to  height  more  nearly  in  accord  with  that  found  with  our  laboratory 
children,  they  would  have  presented  an  even  more  ideal  picture. 
Apparently  they  were  slightly  underweight  for  their  height,  while  our 
laboratory  children,  selected  from  by  no  means  as  good  an  environ- 
ment, showed  a  somewhat  better  proportion  of  weight  to  height — 
better  when  judged  on  the  basis  that  excess  weight  is  advantageous 
during  the  period  of  growth.  For  these  reasons  we  believe  that  all 
curves  which  represent  a  so-called  normal,  either  for  height  or  for 
weight,  are  drawn  at  too  low  a  level,  and  instead  of  using  the  average 
for  normal,  as  is  commonly  done,  a  value  perceptibly  higher  than  the 
average  should  be  striven  for  in  establishing  any  standards  to  represent 
the  ideal  rates  of  growth  in  height  and  weight  for  the  various  ages. 

To  establish  the  normality  of  our  laboratory  children,  then,  we  have 
the  following  proofs.  These  laboratory  children  represent  a  some- 
what better  proportion  of  weight  to  height  than  the  private-school 
children,  represent  a  relationship  of  height  to  age  and  weight  to  age 


PULSE-RATE.  75 

not  quite  so  good  as  the  children  in  private  schools,  but  better  than 
many  of  the  earlier  standards,  and  consequently  may  legitimately  be 
regarded  as  of  a  degree  of  normality  to  satisfy  present-day  criteria. 

PULSE-RATE. 

One  of  the  most  striking  indices  of  apparent  changes  in  metabolic 
activity,  induced  either  by  muscular  activity  or  by  febrile  conditions, 
is  the  pulse-rate.  In  our  earlier  treatment  of  the  physiology  of  normal 
infants,1  we  laid  special  emphasis  upon  the  importance  of  knowing  the 
fluctuations  in  the  activity  as  exhibited  by  the  kymograph  record  of 
the  movements  of  the  crib  and  particularly  upon  the  relationships 
between  this  curve  for  activity  and  both  the  pulse-rate  and  the  metab- 
olism. 

Before  the  study  of  new-born  infants,  our  observations  on  children 
were  so  scattered  and  represented  so  few  normal  subjects  that  we  were 
unable  to  record  normal  pulse-rates  for  children  of  various  ages. 
With  the  new-born  infants,  however,  this  was  perfectly  feasible,  and 
in  the  report  of  that  study,2  data  were  recorded  giving  the  average 
pulse-rate  for  the  first  8  days  after  birth  as  112  on  the  first  day,  and 
for  the  7  subsequent  days  114,  116,  116,  116,  122,  119,  and  126,  re- 
spectively. These  average  values  were  obtained  from  a  considerable 
number  of  counts  for  different  children.  Those  for  the  first  day  after 
birth  represented  50  new-born  infants,  but  on  the  later  days  the  num- 
ber of  subjects  was  less,  particularly  on  the  seventh  and  eighth  days. 

In  our  report  of  the  observations  on  the  few  normal  subjects,  made 
in  the  first  study  of  the  gaseous  metabolism  of  infants,1  we  were 
primarily  interested  in  such  alterations  in  the  pulse-rate  of  an  indi- 
vidual infant  as  were  due  to  changes  in  activity  and  not  in  the  altera- 
tions due  to  changes  in  age.  Accordingly,  in  this  earlier  study  the 
period  of  observation  did  not  exceed  30  to  45  days,  except  with  a 
single  infant.  In  the  accumulation  of  our  new  data,  however,  special 
stress  was  laid  upon  the  trend  of  the  pulse-rate  as  the  age  increased. 
This  could  be  studied  advantageously  in  those  series  of  observations 
in  which  the  metabolism  of  the  same  child  was  studied  over  periods 
of  4  months  or  more,  and  in  a  few  cases  3|  years.  Finally,  with  the 
older  children,  the  unusually  advantageous  conditions  under  which 
the  data  were  obtained  make  it  seem  desirable  for  us  to  record  the 
pulse-rates  and  deduce  therefrom  average  values  which  might  be 
expected  from  children  under  quiet  conditions. 

Even  the  earliest  observers  noted  that  the  pulse-rate  of  infants  was 
very  difficult  to  obtain  and  varied  under  different  circumstances. 
The  great  difficulties  in  securing  accurate  records  can  perhaps  be  no 

1  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914. 

2  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  233,  1915,  table  19,  p.  115. 


76   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

better  expressed  than  by  quoting  from  the  earliest  report  that  we  have 
found  in  English  of  observations  on  the  pulse-rate  of  children. 
Publishing  in  1694,  Walter  Harris  of  London  stated: 

"But  the  Pulses  of  Children  are  naturally,  or  upon  every  little  Alteration, 
do  become  so  swift  and  frequent,  that  they  always  seem  somewhat  Feverish. 
Moreover,  they  are  for  the  most  part,  so  chagreen  and  froward,  that  not 
keeping  their  Wrest  one  moment  in  the  same  posture,  do  not  suffer  their 
Pulse  to  be  touched.  Lastly,  there  are  so  many  things  that  do  accelerate 
or  otherways  change  their  Pulses,  that  Sentiments  taken  thence  should 
prove  very  uncertain,  if  not  altogether  false."  1 

In  the  interesting  book  of  Benjamin  Waterhouse2  we  find  a  quo- 
tation from  a  paper  read  in  1768  at  the  Royal  College  of  Physicians 
in  London  by  the  venerable  Dr.  Heberden: 

"The  pulse  of  children  under  two  years  old  should  be  felt  when  they  are 
asleep;  for  their  pulses  are  greatly  quickened  by  every  new  sensation,  and 
the  occasions  of  these  are  perpetually  happening  to  them  while  they  are 
awake.  The  pulse  then  qf  a  healthy  infant  asleep  on  the  day  of  its  birth, 
is  between  130  and  140  in  one  minute;  and  the  mean  rate  for  the  first 
month  is  120,  for,  during  this  time,  the  artery  often  beats  as  frequently 
as  it  does  the  first  day,  and  I  have  never  found  it  beat  slower  than  108. 
During  the  first  year  the  limits  may  be  fixed  at  108  and  120.  For  the  second 
year  at  90  and  108.  For  the  third  year  at  80  and  100.  The  same  will 
very  nearly  serve  for  the  fourth,  fifth,  and  sixth  years.  In  the  seventh 
year  the  pulsations  will  be  sometimes  so  few  as  72,  though  generally  more; 
and  therefore,  except  only  that  they  are  more  easily  quickened  by  illness, 
or  any  other  cause,  they  will  differ  but  little  from  the  healthy  pulse  of  an 
adult,  the  range  of  which  is  from  a  little  below  60  to  a  little  above  80.  It 
must  be  remembered,  that  the  pulse  becomes  more  frequent,  by  ten  or 
twelve  in  a  minute  after  a  full  meal." 

No  further  evidence  as  to  the  difficulties  of  making  these  physio- 
logical records  is  necessary.  Perhaps  the  best  confirmation  of  this 
evidence  is  the  fact  that  so  little  is  now  known  regarding  the  quiet 
resting  pulse  of  children.  On  looking  over  the  literature  on  the 
normal  pulse-rate  of  children,  it  is  at  once  obvious  that  very  little 
interest  has  been  taken  in  the  subject  and  few  accurate  counts  have 
been  made  which  take  into  consideration  all  the  factors  which  modify 
the  normal  rate  of  the  heart.  It  has  been  the  custom  of  practically 
all  writers  to  report  minimum  and  maximum  pulse-rates  and  to  follow 
what  seems  to  us  the  very  confusing  and  entirely  irrational  procedure 
of  averaging  these  and  reporting  the  result  as  the  average  pulse-rate. 
A  summation  of  our  data  shows  that  any  pulse-rate  above  the  minimum 
is  profoundly  affected  by  the  degree  of  activity;  therefore,  little,  if 
any,  value  can  be  placed  upon  observations  of  pulse-rate  other  than 
those  obtained  with  the  child  in  repose.  It  is  of  importance  to  know 

1  Harris,  An  exact  enquiry  into,  and  cure  of  the  acute  diseases  of  infants.     London,  1694,  p.  9. 
*  Waterhouse,  An  essay  concerning  tussis  convulsiva  or  whooping  cough,  with  observations  on 
the  diseases  of  children.    Boston,  1822. 


PULSE-KATE.  77 

to  what  extent  maximum  pulse  may  develop  during  paroxysms  of 
crying  and  with  such  activity  as  a  child  may  exhibit  when  lying  in 
bed,  but  for  all  normal  purposes  such  records  have  but  little,  if  any, 
scientific  value. 

The  younger  the  infant  the  greater  is  the  difficulty  of  obtaining  the 
pulse-rate.  With  older  children  the  element  of  apprehension  should 
not  be  entirely  disregarded.  If  this  apprehension  is  not  present  to 
any  great  degree,  the  special  precautions  necessary  for  small  children 
will  not  be  required  for  the  older  individuals.  Our  measurements 
were  all  made  while  the  child  was  inside  a  hermetically  sealed  chamber, 
and  the  routine  was  invariable  for  all  children  studied. 

METHODS  OF  OBTAINING  PULSE-RATE. 

The  pulse-rate  can  be  obtained  either  by  palpation  at  the  wrist 
or  by  direct  auscultation  from  the  heart.  During  infancy  it  is  difficult 
to  obtain  an  accurate  pulse-rate  from  the  wrist,  because  infants  rarely 
remain  quiet  for  more  than  a  few  seconds.  Infants  dislike  to  be  forced 
to  stay  in  one  position,  and  when  made  to  do  so  they  usually  struggle 
and  cry.  It  is  often  impossible  to  get  the  pulse-rate  from  the  wrist 
while  the  infant  is  asleep,  for  the  slightest  touch  of  the  observer's 
hand  wakens  the  child.  The  difficulties  present  during  the  waking 
hours  are  then  accentuated  by  the  fright  which  may  result  from  the 
sudden  awakening.  Obtaining  the  pulse-rate  by  means  of  a  stetho- 
scope held  over  the  heart  is  also  attended  by  many  difficulties.  Unless 
an  infant  is  phlegmatic  or  becomes  used  to  this  procedure,  he  may 
squirm  and  cry  and  sometimes  violently  resist  the  application  of  the 
stethoscope.  When  a  child  or  an  infant  resists,  it  is  obviously  im- 
possible for  the  observer  both  to  hold  the  stethoscope  on  the  chest- 
wall  and  to  make  an  accurate  record  of  the  pulse-rate  unless  someone 
holds  the  infant. 

The  most  successful  method  of  obtaining  an  accurate  pulse-rate  is 
by  means  of  a  small  Bowles  stethoscope  fastened  with  adhesive  plaster 
to  the  body-surface  of  the  infant  over  the  heart.  A  long  rubber  tube 
is  run  from  the  stethoscope  under  the  clothing  and  out  to  the  earpieces. 
The  child  can  then  take  any  position  he  desires  without  feeling  that 
he  is  restricted  and  without  realizing  that  the  stethoscope  has  been 
applied.  All  of  our  own  pulse-counts  were  obtained  by  this  method. 

In  full  recognition  of  the  difficulties  attending  a  study  of  the  pulse- 
rate,  we  have  tabulated  the  results  of  our  observations,  taking  into 
consideration  only  the  minimum  pulse-rate.  Our  studies  contribute 
towards  the  solution  of  two  main  physiological  problems:  First,  how 
does  the  pulse-rate  vary  with  age;  secondly,  what  is  the  average 
pulse-rate  for  children  of  various  ages?  Since  the  number  of  observa- 
tions made  was  considerable,  the  results  offer  a  fair  basis  for  answering 
these  questions. 


78       METABOLISM   AND   GROWTH   FROM   BIRTH   TO   PUBERTY. 


INFLUENCE  OF  AGE  UPON  THE  PULSE-RATE. 

The  pulse-rate  at  the  end  of  fetal  life  is  said  to  average  between  135 
and  140  per  minute,  but  it  is  only  with  extra-uterine  pulse-rate  that 
our  observations  deal.  In  the  study  of  new-born  infants  we  were 
able  in  no  case  to  make  observations  of  the  pulse-rate  of  the  same 
child  throughout  the  entire  first  week.  The  average  pulse-rates  for 
the  first  seven  or  eight  days  of  life  given  in  the  report  of  that  study 
must  consequently  be  looked  upon  as  showing  only  the  general  trend 
of  the  average  pulse-rates  of  new-born  children. 

In  our  first  report  we  tabulated  all  of  the  available  data  for  the 
pulse^rate  for  each  of  the  first  8  days  after  birth,  regardless  of  whether 
the  measurement  of  the  metabolism  during  these  periods  gave  strictly 
minimum  results  or  not.1  Our  conclusions  were  based  upon  these 
pulse  data,  but  it  was  definitely  stated  that  the  values  for  the  pulse- 
rate  were  those  of  infants  during  periods  of  approximately  minimum 
heat  production  and  that  the  metabolism  during  these  periods  could 
be  considered  as  absolutely  minimum  in  only  a  relatively  few  cases. 
In  this  publication  it  seems  best  to  present  the  data  for  the  pulse-rate 
of  new-born  infants  for  comparison  purposes,  using  as  a  basis  of 
selection,  however,  the  periods  in  which  the  minimum  heat  production 
was  obtained.  The  pulse-rates  for  these  periods  of  minimum  heat 
production  are  given  in  table  16.  A  comparison  of  the  figures  for 

TABLE  16. — Pulse-rate  during  first  8  days  after  birth. 


Age. 

No.  of 
subjects. 

Average 
pulse-rate. 

First  day  

50 

112 

Second  day  

25 

110 

Third  day  

19 

109 

Fourth  day  

20 

116 

Fifth  day  

14 

113 

Sixth  day  
Seventh  day  . 

7 
4 

118 
114 

Eighth  day.  .  .  . 

95 

pulse-rate  given  in  the  earlier  report2  with  those  in  table  16  shows  that 
this  later  method  of  selection  lowered  the  daily  averages  on  all  but 
the  first  and  fourth  days,  there  being  no  change  on  these  days;  that 
is,  when  the  effort  is  made  to  tabulate  only  pulse-rates  with  minimum 
heat  production,  in  most  cases  this  approximation  to  the  minimum  heat 
production  is  accompanied  by  a  distinct  reduction  in  the  average  pulse- 
rate.  Since  all  of  the  subsequent  material  on  pulse-rate  in  this  report 
is  based  upon  the  values  found  during  minimum  muscular  activity, 
for  the  final  summation  of  pulse-rate  values  for  children  the  averages 
given  in  table  16  will  be  used  rather  than  those  in  the  earlier  report. 

1  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  233,  1915,  table  19,  p.  115. 
'Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  233,  1915.  p.  116. 


PULSE-RATE. 


79 


TABLE  17. — Basal  pulse-rate  of  boys  at  different  ages. 


No.  of 
subject. 

1 
mo. 

H 

mo. 

2 
mo. 

2J 
mo. 

3 
mo. 

4 
mo. 

5 

mo. 

6 
mo. 

7 
mo. 

8 
mo. 

9 
mo. 

10 
mo. 

11 
mo. 

61 

136 

115 

118 

124 
94 
126 
123 

130 
120 
117 

130 



138 

130 

128 

112 

121 

117 

118 

109 

127 

122 
121 

119 

104 

119 

122 

121 

124  

120 
125 

115 
120 
111 

125.. 
126.. 
128.. 
129.. 
130.. 
132.. 
133 

111 
110 
116 
109 
113 
123 

113 

107 

iis 

118 
134 
114 
115 

119 

136.. 
137.. 
138 

129 

116 



119 

114 



132 

133 
124 

129 

116 

141 

142 

122 

115 
119 
108 

103 
107 
117 
101 
109 
110 

117 

104 

116 

147. 
148. 
149. 
150. 
153. 
154..  .  . 

112 

112 

111 

iio 

127 
115 
126 
120 

iii 
112 

iis 
iis 

iis 
ii7 

155..  .  . 
156..  .  . 
157 

158 

123 
119 

115 

95 

159 

161 

123 

145 
108 





164.. 
168.. 
170.. 

118 

109 

109 

No.  of 
sub- 
ject. 

12 
mo. 

14 
mo. 

16 
mo. 

18 
mo. 

20 
mo. 

22 
mo. 

24 
mo. 

26 
mo. 

28 
mo. 

30 
mo. 

32 
mo. 

34 
mo. 

36 
mo. 

38 

mo. 

119.. 
138.  . 
148.. 
153.  . 
155.  . 
158.. 
161 

112 
118 

125 

110 
111 

108 
106 
106 

92 
127 

104 

94 
96 

103 

107 

107 

101 

100 

110 
107 
93 

86 

93 
96 
83 

98 
83 

"75" 

135 

123 
126 



112 

116 

107 

84 

87 

175 

94 
85 

176 

For  the  first  5  days  after  birth  the  number  of  infants  is  sufficiently 
large  to  justify  a  study  of  the  general  trend  of  the  pulse-rate  during 
this  time.  On  the  last  3  days  the  number  is  obviously  too  few,  but 
the  results  are  included  here  to  complete  the  data.  From  this  table 
it  can  be  seen  that  there  is  a  slight  tendency  for  the  pulse-rate  to  rise 
and  remain  at  the  higher  level  after  the  first  3  days,  with  a  tendency 
to  decrease  successively  on  the  first  3  days.  All  of  these  values  are 
measurably  less  than  that  reported  for  the  last  hours  of  fetal  life. 


80   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


TABLE  18. — Basal  puke-rate  of  girls  at  different  ages. 


No.  of 
subject. 

9th 
day. 

llth 
day. 

12th 
day. 

2 
wks. 

3 

wks. 

1 
mo. 

li 

mo. 

2 
mo. 

2| 
mo. 

3 

mo. 

4 
mo. 

5 
mo. 

6 
mo. 

2 

94 

97 

95 

112 

35 

134 

125 

48 

127 

159 

139 

49 

115 

126 

110 

118 

125 

113 

146 

134 

132 

134 

120 

134 

120 

116 

121 

116 

123 

132 

120 

123 

122 

125 

138 

135 

123 

130 

125 

122 

121 

127 

117 

131 

121 

127 

121 

127 

134 

106 

135 

103 

110 

139 

131 

126 

140 

113 

118 

111 

121 

145 

117 

146 

121 

132 

151 

126 

152  

121 

No.  of 
subject 

7 
mo. 

8 
mo. 

9 
mo. 

10 
mo. 

11 
mo. 

12 
mo. 

14 
mo. 

16 
mo. 

18 
mo. 

20 
mo. 

22 
mo. 

24 
mo. 

122 

138 

132 

123 

113 

115 

127 

125 

115 

113 

114 

109 

100 

131 

120 

122 

139 

128 

128 

123 

133 

117 

122 

110 

103 

145 

117 

110 

108 

109 

98 

103 

88 

83 

146 

122 

160 

123 

126 

125 

115 

116 

162 

119 

163 

116 

165 

101 

166  

111 

128 

126 

117 

105 

100 

106 

88 

167 

127 

171  

132 

165 

136 

119 

123 

116 

114 

172  

123 

124 

118 

119 

106 

173 

121 

120 

111 

103 

174 

104 

No.  of 

subject 

26 
mo. 

28 
mo. 

30 
mo. 

32 
mo. 

34 
mo. 

36 

mo. 

38 
mo. 

40 
mo. 

42 
mo. 

44 
mo. 

46 
mo. 

4 
yr. 

139  

110 

100 

93 

91 

80 

82 

85 

145  

73 

70 

76 

74 

71 

70 

166  

98 

86 

96 

90 

90 

76 

171  

111 

101 

91 

90 

178  

88 

180  

91 

181  

88 

183  

78 

184  

93 

In  the  present  report  we  are  more  particularly  interested  in  the 
pulse-rates  of  children  over  a  week  old.    To  eliminate  completely  the 


PULSE-RATE.  81 

possibilities  of  sexual  differentiation,  a  subject  which  will  be  discussed 
somewhat  later  in  this  report,  we  have  tabulated  the  values  for  boys 
and  girls  separately,  those  for  boys  appearing  in  table  17  and  those  for 
girls  in  table  18.  Unlike  the  average  pulse-rates  for  new-born  infants 
shown  in  table  16,  the  pulse  data  presented  in  tables  17  and  18  do  not 
represent  the  pulse-rates  obtained  in  the  periods  of  minimum  heat 
production.  The  basis  of  selection  here  used  was  the  degree  of  muscu- 
lar repose,  the  pulse-rates  tabulated  being  those  obtained  in  periods 
of  minimum  activity,  as  indicated  by  the  tracings  on  the  kymograph, 
without  reference  to  the  heat  production.  The  pulse-rates  of  boys 
and  girls  as  presented  in  these  tables  offer  an  opportunity  for  studying 
the  basal  pulse-rate  of  the  same  child  at  varying  ages.  This  is  par- 
ticularly true  of  boys  up  to  the  age  of  38  months  and  of  girls  up  to 
4  years. 

One  of  the  longest  series  for  boys  is  that  with  No.  119.  The  irregu- 
larities in  the  figures  reported  for  this  subject  show  clearly  that  there 
is  very  little  evidence  of  a  definitely  established  trend  until  the  child 
is  somewhat  over  a  year  old,  but  that  during  the  second  year  there 
is  a  distinct  tendency  for  the  pulse-rate  to  decrease.  Another  long 
series  is  represented  by  No.  158.  Here  again  considerable  irregularity 
is  noted  previous  to  the  age  of  14  months ;  thereafter  there  is  a  reason- 
ably uniform  decrease.  These  irregularities  during  the  first  14  months 
are  to  be  observed  with  practically  all  of  the  boys.  During  the  second 
year  of  life,  however,  the  values  indicate  a  definite  tendency  toward  a 
generally  lowering  pulse-rate. 

This  finding  with  boys  is  likewise  noticeable  with  girls,  although  the 
irregularity  in  the  first  year  is  by  no  means  so  striking.  Indeed,  with 
a  number  of  subjects  there  is  a  reasonable  degree  of  decrease  in  the 
pulse-rate  subsequent  to  the  age  of  4  or  5  months.  It  is  characteristic 
of  all  these  children,  however,  that  after  the  first  year  and  a  half  the 
decrease  is  reasonably  well  established. 

AVERAGE  PULSE-RATE  OF  CHILDREN. 

The  second  important  factor  to  which  our  data  contribute  is  the 
average  pulse-rate  of  children  of  the  same  age,  both  as  to  its  absolute 
value  and  as  to  the  deviation  therefrom  which  can  be  expected  for 
children  in  repose.  With  boys,  one  of  the  most  extensive  series 
numerically  that  we  have  for  any  age  represented  in  table  17  is  that 
for  the  group  7  months  old,  in  which  the  basal  pulse-rate  for  the  13 
boys  ranged  from  107  (No.  126)  to  127  (No.  154).  The  average  for 
this  group  is  found  to  be  117.  It  is  clear,  therefore,  that  it  is  only 
with  a  great  deal  of  reserve  that  one  may  speak  of  the  pulse-rate  of  a 
boy  of  7  months  as  being  117.  Even  wider  differences  are  observed 
with  the  4  boys  of  20  months,  the  lowest  being  92  and  the  highest  127, 
with  an  average  of  111. 


82   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


From  the  foregoing  discussion  of  the  considerable  variation  to  be 
found  with  an  individual  in  the  earlier  years,  one  would  naturally 
expect  similar  large  differences  between  groups  of  older  children  of  the 
same  age.  The  considerable  amount  of  data  obtained  for  the  first 
four  years  of  a  child's  life  have  been  supplemented  by  records  for  older 
children,  which  are  given  in  table  19  for  boys  and  girls  5  to  13  years 

TABLE  19. — Basal  pulse-rate  of  individual  children  5  to  13  years  of  age. 


B( 

>ys. 

Gi 

rls. 

6 
yrg. 

7 

yrs. 

8 
yrs. 

9 

yrs. 

10 

yrs. 

11 

yrs. 

12 

yrs. 

13 

yrs. 

5 

yrs. 

7 
yrs. 

8 
yrs. 

9 

yrs. 

10 

yrs. 

12 

yrs. 

90 
72 
86 

99 
74 
84 
83 
85 

79 
79 

94 

84 
71 
73 
86 
78 

80 
81 
89 

89 
82 
76 
69 
76 

67 
68 
67 
66 
65 

74 
68 
71 
80 

114 
79 
82 
90 

76 

74 
71 

76 

86 
69 

83 

97 

83 
85 
88 

84 

85 
69 
80 

74 

76 

78 

81 

78 

79 

71 

77 

72 

67 

69 

of  age.  Almost  without  exception,  however,  the  averages  in  this 
table  represent  individual  children,  the  data  for  each  child,  except  in 
one  case,  being  obtained  at  only  one  age.  Here  again  we  find  con- 
siderable differences.  Thus,  for  the  7  boys  7  years  of  age,  the  lowest 
is  74  and  the  highest  99.  With  the  5  boys  9  years  of  age,  the  lowest 
record  is  71  and  the  highest  86,  while  the  9  boys  11  years  of  age  show  a 
maximum  difference  in  their  basal  pulse-rates  of  22  beats. 

With  girls,  one  of  the  largest  groups  at  the  earlier  ages  is  that  for 
6  months,  but  the  pulse-rates  for  these  8  girls  range  only  from  118  to 
132,  with  an  average  of  124.  This  approach  to  uniformity,  which  is 
much  closer  than  that  noted  for  boys,  does  not  by  any  means  hold  for 
all  ages,  since  at  16  and  18  months  differences  amounting  to  40  and 
32  beats,  respectively,  are  observed.  The  largest  group  for  the  older 
ages  represented  in  table  19,  that  for  9  years,  has  values  for  pulse-rate 
for  the  6  girls  ranging  from  71  to  97.  The  extraordinarily  high  value 
of  114  for  one  of  the  5-year-old  girls  may  have  some  special  explanation 
which  is  at  present  unknown  to  us. 

Bearing  in  mind  the  irregularities  seen  in  the  careful  examination 
of  the  data  for  these  several  age-groups,  we  may  average  these  pulse 
data  and  attempt  to  portray  the  general  trend  of  the  minimum  or 
basal  pulse-rate  of  boys  and  girls  from  birth  to  13  years  of  age.  In  so 
doing  we  have  left  out  of  the  averaging  all  age-ranges  represented  by 
less  than  three  individuals.  These  values  are  brought  together  in 
table  20. 

The  average  values  shown  for  boys  indicate  a  reasonably  constant 
pulse-rate  for  the  first  14  months  of  life,  ranging  from  113  to  125,  if 


PULSE-RATE. 


83 


TABLE  20. — Comparison  of  average  minimum  pulse-rates  of  boys  and  girls. 


Age. 

Boys. 

Girls. 

Age. 

Boys. 

Girls. 

No.  of 
sub- 
jects. 

Average 
mini- 
mum 
pulse- 
rate. 

No.  of 
sub- 
jects. 

Average 
mini- 
mum 
pulse- 
rate. 

No.  of 
sub- 
jects. 

Average 
mini- 
mum 
pulse- 
rate. 

No.  of 
sub- 
jects. 

Average 
mini- 
mum 
pulse- 
rate. 

Iday  . 
2  days  . 
3  days  . 
4  days  . 
5  days  . 
6  days  . 
11  days. 

29 
13 
8 
11 
11 

113 
108 
105 
117 
114 

21 
12 
11 
9 
3 
5 
3 
3 
3 
5 

6 
6 
8 
8 
5 
4 
5 
5 
3 
7 
8 

110 
112 
112 
114 
111 
118 
110 
132 
138 
129 

129 
119 
119 
124 
121 
121 
116 
124 
118 
124 
121 

16  mos 

8 
7 
3 
4 
4 
3 
3 

114 
115 
105 
103 

97 
94 
89 

87 
84 
79 
88 
87 
91 

18  mos. 
20  mos. 
22  mos. 
24  mos. 
26  mos. 
28  mos. 
30  mos. 
34  mos. 
38  mos. 
40  mos. 
46  mos. 

5 
4 
3 

4 

107 
111 
106 
94 

5 
3 

98 
91 

l|  mos.  . 
2  mos.  .  . 
2?  mos.  . 
3  mos.  .  . 
4  mos..  . 
5  mos.  .  . 
6  mos.  .  . 
7  mos.  .  . 
8  mos.  .  . 
9  mos.  .  . 
10  mos.  .  . 
11  mos.  .  . 
12  mos.  .  . 
14  mos.  .  . 

5 
6 
5 

7 
9 
8 
11 
13 
8 
7 
7 

3 
3 

117 
125 
117 
116 
124 
119 
115 
117 
117 
114 
113 

122 

125 

3 
3 
4 
3 
3 
4 

4yrs.     . 

6yrs. 

7yrs. 
8yrs. 
9yrs. 
lOyrs. 
11  yrs.  . 
12yrs.  . 
13  yrs.  . 

3 

7 
4 
5 
3 
9 
6 
4 

83 
83 
80 
78 
83 
75 
69 
73 

3 
3 

6 
4 

74 
77 
85 
80 

3 

76 

we  exclude  the  first  5  days,  and  from  105  to  125  if  these  earlier  values 
are  included.  Thereafter  the  picture  is  a  gradual  decrease,  persisting 
throughout  the  second  and  much  of  the  third  year.  The  data  between 
3  and  6  years  are  lacking.  During  this  period  there  has  been  a  very 
considerable  fall,  the  tendency  to  a  decrease  continuing  subsequent 
to  7  years.  The  lowest  value  is  69  at  the  age  of  12  years.  With  girls, 
the  averages  show  that  after  the  first  11  days  there  is  a  distinct  ten- 
dency for  a  rise  in  pulse-rate,  the  return  to  the  rate  of  the  first  week 
not  taking  place  until  shortly  after  the  end  of  the  first  year.  There  is 
then  a  continued  decrease,  the  lowest  record  being  74  at  the  age  of 
7  years. 

SEX  AND  MINIMUM  PULSE-RATE. 

The  intimate  relation  between  pulse-rate  and  metabolism,  shown 
with  the  same  individual  in  the  large  majority  of  observations  hi  this 
laboratory,  makes  a  careful  examination  of  pulse-rate  with  respect  to 
sex  of  special  importance.  The  analysis  of  data  for  the  basal  metab- 
olism of  men  and  women  has  shown  that  women  as  a  class  have  a 
lower  metabolism  than  men,  not  only  per  individual,  but  per  unit  of 
weight.  On  the  other  hand,  the  pulse-rate  of  women  as  a  class  was 
shown  to  be  higher  than  that  of  men,  as  measurements  for  90  women 
and  121  men  in  our  series  gave  an  average  of  68.67  for  women  and 


84   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

61.26  for  men.1  These  differences  are  substantiated  by  the  fact  that 
with  men  three  different  groups  of  28,  116,  and  50  men  showed  average 
pulse-rates  of  62.5, 61.3,  and  61.3,  respectively.  Two  groups  of  women, 
one  of  68  and  the  other  of  22,  showed  pulse-rates  of  69.1  and  67.3, 
respectively.  In  other  words,  it  seems  thoroughly  established  that 
the  women  as  a  class  have  a  pulse-rate  somewhat  higher  than  men,  in 
spite  of  the  fact  that  their  metabolism  is  distinctly  lower.  This  sup- 
plies very  clear  evidence  that  while  pulse-rate  and  heat  production 
may  be  closely  correlated  in  the  same  individual,  in  groups  of  indi- 
viduals the  pulse-rate  may  vary  enormously  and  " average"  pulse-rate 
may  have  little,  if  any,  connection  with  " average"  heat  production. 

Since  the  pulse-rates  of  men  and  women  show  a  difference,  it  becomes 
extremely  important,  in  studying  our  groups  of  children,  to  note  at 
what  point,  if  any,  there  is  a  definite  change  in  the  pulse-rate,  and 
further  comparisons  of  values  for  males  and  females  will  be  of  special 
interest  in  this  connection.  Such  comparison  may  be  made  from  the 
pulse-rate  data  for  boys  and  girls  in  table  20,  which  gives  an  oppor- 
tunity of  noting  the  differentiation,  if  any,  due  to  sex.  To  this  end, 
wherever  values  for  both  boys  and  girls  are  recorded  at  the  same  age, 
the  higher  of  the  two  values  has  been  italicized.  Thus,  for  children 
1  day  old,  29  boys  gave  an  average  minimum  pulse-rate  of  113,  while 
21  girls  had  a  pulse-rate  of  110.  On  the  next  day  the  conditions  for 
very  nearly  the  same  number  of  boys  as  girls  were  reversed,  the  girls 
showing  a  pulse-rate  4  beats  higher  than  the  boys. 

Pursuing  this  method  of  analysis  for  the  entire  group  of  data  in 
table  20,  and  passing  over  those  ages  for  which  records  are  available 
for  only  one  of  the  two  sexes,  we  find  that  at  11  age-periods  the  boys 
have  a  higher  pulse-rate  than  the  girls  of  the  same  age,  while  at  15 
age-periods  the  girls  have  a  higher  pulse-rate  than  boys  of  like  age. 
On  this  basis,  therefore,  it  would  appear  that  the  pulse-rate  of  the 
girls  was,  on  the  whole,  somewhat  higher  than  that  of  boys.  The 
italicized  figures  in  the  table  show  no  great  regularity  in  the  appear- 
ance of  these  high  values  with  either  sex.  The  most  consistent  record 
is  that  from  1|  months  to  10  months,  the  only  ages  at  which  the  girls 
are  not  higher  being  that  of  4  months,  and  again  of  5  months,  when  the 
average  pulse-rate  for  both  sexes  is  the  same.  After  10  months  the 
italicized  figures  indicate  but  little  regularity  as  to  sex. 

On  the  whole,  the  picture  can  not  be  said  to  speak  pronouncedly  for 
a  higher  pulse-rate  with  girls  than  with  boys.  In  making  this  general 
conclusion,  however,  it  is  important  to  note  that  the  data  under  con- 
sideration are  at  best  somewhat  meager,  although  they  may  be  relied 
upon  as  far  as  they  go.  But  many  observations  of  the  minimum 
resting  pulse-rate  of  boys  and  girls  are  necessary  before  final  conclusions 

1  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  66. 


RECTAL   TEMPERATURE. 


85 


can  be  drawn,  for  obviously  the  pulse-rate  at  other  ages  should  be 
studied  and  supplementary  data  should  be  obtained  for  the  higher 
ages  included  in  our  observations. 

AVERAGE  PULSE-RATE  WITH   INCREASING  AGE. 

From  the  foregoing  analysis  it  can  be  seen  that  there  is  no  striking 
difference  between  the  pulse-rates  of  girls  and  boys.  Accordingly,  as 
a  tentative  measure  of  the  average  minimum  resting  pulse-rate  of 
children  of  both  sexes,  we  have  taken  the  values  given  in  table  21 
as  approximately  normal  values.  In  view  of  the  special  conditions 
under  which  these  pulse-rates  were  obtained,  namely,  complete  muscu- 
lar repose  and  with  the  subject  entirely  unconscious  of  the  records,  it 
is  seen  that  we  have  here  true  physiological  values  uncontaminated  by 
activity. 

TABLE  21. — Approximate  normal  minimum  values  for  pulse-rates  of  children 
during  complete  muscular  repose. 


End  of  year. 

Av.  min. 
pulse-rate. 

End  of  year. 

Av.  min. 
pulse-rate. 

First  
Second  

122 
100 

Seventh  
Eighth  

78 
78 

Third  

89 

Ninth          

82 

Fourth.  . 

87 

Tenth 

81 

Fifth  .... 

91 

Twelfth 

72 

RECTAL  TEMPERATURE. 

Any  physiological  study  of  body  temperature,  to  be  of  true  scientific 
value,  must  deal  with*  temperatures  taken  deep  in  the  body  trunk. 
The  extraneous  factors  of  exercise,  mouth-breathing,  and  the  effect  of 
previously  taken  foods  so  greatly  vitiate  all  measurements  of  the  buccal 
temperature  that  they  have  little,  if  any,  value  except  for  demon- 
strating the  absence  of  fever.  It  has  been  the  custom  of  many  clini- 
cians to  take  the  temperature  of  young  children  in  the  axilla  or  in  the 
groin.  These  records,  aside  from  likewise  showing  the  presence  or 
absence  of  fever,  have  no  physiological  value,  for  it  has  been  found 
that  even  when  these  cavities  are  well-closed  a  very  considerable  period 
of  time  is  required  to  raise  their  temperature  to  that  approximating 
the  interior  of  the  body. 

In  our  study  of  certain  physiological  factors  during  growth,  the 
rectal  temperature  was  measured  primarily  to  demonstrate  the 
absence  of  any  febrile  condition,  since  the  presence  of  fever  would  of 
course  preclude  further  observations  with  the  child  in  this  abnormal 
state.  Every  reasonable  effort  was  made  to  have  these  measurements 
meet  the  exactions  of  scientific  accuracy,  but  as  ordinary  clinical 
mercury  thermometers  were  used,  even  though  well-tested,  and  there 


86   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

were  changes  in  the  personnel  of  the  assistants  from  time  to  time, 
as  well  as  possibilities  of  difference  in  the  depth  of  insertion  of  the 
thermometer  bulb,  we  may  not  look  upon  these  observations  as  a 
refined  physiological  study  of  changes  in  body  temperature  of  children. 

It  is  to  be  regretted  that  a  study  of  the  diurnal  rhythm  of  the  rectal 
temperature  of  children  of  various  ages  could  not  have  been  included 
in  the  research,  but  this  was  impracticable.  To  use  occasional  obser- 
vations of  rectal  temperature  as  a  basis  for  determining  the  physio- 
logical temperature  of  children  is  open  to  serious  question,  since  the 
well-known  influences  of  activity,  ingestion  of  food,  and  sleep  make 
such  measurements  liable  to  gross  variability.  When  one  considers 
that  the  normal  range  in  temperature  is  but  2°  or  3°  F.,  it  will  be  seen 
that  if  a  study  of  the  body  temperature  is  to  be  made  with  strict 
scientific  accuracy,  a  much  more  sensitive  measurement  should  be 
used  than  that  employed  in  this  research.  But  as  the  measurements 
were  all  made  with  the  child  inside  a  chamber,  lying  quietly  on  a 
comfortable  bed,  we  believe  that  although  the  method  was  admittedly 
defective,  the  conditions  were  essentially  comparable  and  the  values 
may  legitimately  be  used  for  drawing  conclusions. 

The  rectal  temperature  was  usually  recorded,  at  least  with  the 
younger  children,  just  before  and  just  after  each  respiration  experiment. 
Several  hundred  observations  of  the  body  temperature  of  these  children 
were  thus  obtained.  It  appeared  unnecessary  to  give  detailed  publi- 
cation of  all  these  records,  and  we  have  therefore  averaged  the  two 
observations  for  each  experiment  and  grouped  them  in  table  22,  accord- 
ing to  sex,  as  general  averages  for  certain  average  ages.  In  these 
averages  the  relatively  few  records  of  100.5°  F.  or  over  have  not  been 
included.  The  number  of  observations  entering  into  each  average  is 
also  shown  hi  the  table.  If  measurements  were  made  with  but  a 
single  subject  for  any  particular  age,  the  values  were  not  included  in 
this  comparison.  From  these  average  values  an  indication  of  the 
general  trend  of  the  body  temperature  of  children  during  the  period 
of  growth  may  be  obtained. 

The  values  for  boys  range  from  97.1°  F.,  the  very  low  value  for  the 
two  boys  averaging  5  years  of  age,  to  a  maximum  of  99.5°  F.  in  the 
group  of  six  boys  for  If  years.  During  the  first  month  or  two  of  life 
the  temperatures  for  boys  are  somewhat  low,  but  with  evidence  of  a 
tendency  to  rise  thereafter,  the  maximum  continuing  for  approximately 
two  or  three  years.  Subsequently  the  figures  incline  to  run  below 
rather  than  above  99°  F.,  and  after  10  years  all  values  are  98.8°  F. 
or  under.  Special  attention  has  already  been  called  to  the  extra- 
ordinarily low  value  of  97.1°  F.  for  the  two  boys  5  years  of  age,  which 
must  not  be  looked  upon  as  characteristic  of  that  age. 

This  table  must  not  be  considered  as  indicating  the  minimum  tem- 
peratures at  these  various  ages.  According  to  previous  experimenting 


RECTAL   TEMPERATURE. 

TABLE  22. — Average  rectal  temperature  of  boys  and  girls  ttf  different  ages. 


87 


Boys. 

Girls. 

No.  of 
subjects. 

No.  of 
meas- 
ure- 
ments. 

Average 
age. 

Aver- 
age 
rectal 
tem- 
pera- 
ture.1 

No.  of 
subjects. 

No.  of 

meas- 
ure- 
ments. 

Average 
age. 

Aver- 
age 
rectal 
tem- 
pera- 
ture.1 

44 
34 

88 
68 

f  hr.  to  24  hrs  
1  to  2  days  > 

°F. 
298.2 
298.7 

30 
31 

60 
62 

f  hr.  to  24  hrs  
1  to  2  days 

°F. 
298.3 

298  8 

31 

62 

2  to  3  days.  . 

298.8 

29 

58 

2  to  3  days 

299  0 

27 

54 

3  to  4  days 

298.5 

24 

48 

298  7 

22 

43 

4  to  5  days 

298  5 

18 

36 

*98  5 

9 

17 

5  to  6  days 

298  7 

13 

26 

5  to  6  days 

*98  5 

10 

20 

6  to  7  day 

298  5 

6 

12 

6  to  7  days 

*98  6 

6 

12 

7  to  8  days  

298.8 

3 

6 

7  to  8  days  

298.7 

7 
6 

22 
19 

8  to  20  days  

98.7 
98  7 

8 
4 

30 
16 

8  days  to  3  wks  

98.5 
98  9 

8 

50 

2  mos  

99.0 

6 

22 

2  mos  

99.1 

8 
8 

30 
36 

3  mos  
4  mos  

99.1 
99.0 

7 
7 

27 
38 

3  mos  
4  mos  

98.9 
98.8 

8 
11 

30 
40 

5  mos  
6  mos  

99.1 
99.0 

9 

8 

32 
35 

5  mos  
6  mos  

98.9 
98.9 

13 

47 

7  mos  

99.0 

6 

24 

7  mos  

98.9 

6 

20 

8  mos  

990 

4 

10 

8  mos  

98.9 

8 

32 

9  mos.        .    . 

988 

8 

26 

9  mos  

99.3 

4 

18 

10  mos. 

99  1 

5 

14 

10  mos  

99.1 

5 

18 

1  yr. 

99  3 

5 

16 

99.5 

6 

58 

1±  yrs 

99  5 

8 

89 

1  yr.   . 

99.4 

5 

23 

2  yrs 

99  3 

8 

74 

Ij  yrs..  .    . 

99.5 

6 

26 

2|  yrs  

99.0 

6 

46 

2  yrs  

99.4 

3 

16 

3  yrs 

99  1 

4 

30 

2j  yrs 

99.3 

2 

2 

97  1 

5 

30 

3  yrs. 

99.2 

2 

7 

4 
21 

5|yrs  
7  yrs  

98.4 
99.1 

5 

4 

19 
13 

3^  yrs  
4  yrs  

99.2 
98.9 

5 

15 

8  yrs  

98.6 

4 

7 

4|  yrs  

98.4 

3 

7 

8|  yrs 

99  2 

3 

4 

51  yre 

98.1 

2 

4 

99  1 

2 

4 

65  yrs 

98.5  " 

3 

6 

9§  yrs. 

99.1 

3 

6 

8  yrs  

98.8 

2 

6 

10J  yrs. 

98  6 

5 

15 

9  yrs  

98.4 

2 

10 

11  yrs. 

98  6 

2 

4 

Qi  yrs  

98.8 

3 

10 

Ill  yrs 

98  3 

2 

5 

10|  yrs  

98.8 

2 

6 

12|  yrs 

98  7 

2 

5 

11  yrs  

98.8  x 

3 

7 

12  yrs  

98.6 

1  Any  reading  of  100.5°  F.  or  over  was  excluded  from  these  averages. 

2  Data  obtained  from  table  9,  Carnegie  Inst.  Wash.  Pub.  No.  233,  1915,  pp.  46-79. 

in  this  laboratory,  the  minimum  temperature  was  found  some  time 
during  the  early  morning  hours,  when  the  subjects  were  in  deep  sleep 
and  the  stomachs  practically  empty.  As  an  indication  of  the  influence 
of  age,  however,  we  believe  that  these  values  are  not  without  sig- 
nificance. It  is  important  to  call  attention  here  to  the  fact  that  the 
period  of  highest  average  rectal  temperature,  as  shown  by  these  more 
or  less  heterogeneous  data  for  boys,  is  not  far  from  10  months  to  2 
years.  As  will  be  seen  later,  this  corresponds  to  the  period  of  relatively 
highest  metabolism.  While  the  evidence  is  by  no  means  beyond 
criticism,  it  is  of  significance  at  least  to  point  out  this  coincidence 


88   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

between  the  maximum  metabolism  and  the  high  average  rectal  tem- 
perature. 

The  values  obtained  with  girls  are  somewhat  better  distributed  for 
the  different  ages  than  those  with  the  boys.  These  range  from  a 
minimum  of  98.3°  F.  for  girls  on  the  first  day  of  life,  to  a  maximum  of 
99.5°  F.  at  11  months  and  If  years  of  age.  Here  again  we  find  a  rela- 
tively low  temperature  in  the  first  few  weeks  of  life  with  a  subsequent 
rise  and  a  high  period  from  11  months  to  2  years  of  age.  Thereafter 
the  temperatures  with  girls  begin  to  fall  and  subsequent  to  3^  years 
are  below  99°  F.  In  this  respect,  therefore,  the  picture  exhibited  by 
the  average  temperature  values  for  girls  confirms  in  a  striking  manner 
that  noted  for  boys.  Here,  also,  the  maximum  level  in  the  body  tem- 
perature, i.  e.,  from  11  months  to  2  years,  corresponds  to  the  maximum 
level  for  the  metabolism,  which  will  be  subsequently  noted.  No  pro- 
nounced sex  differentiation  in  the  values  for  boys  and  girls  is  apparent 
from  these  two  groups  of  data. 

While  it  seemed  inadvisable  to  publish  the  individual  records  of  the 
body  temperature,  the  data  have  been  carefully  compared  to  note  the 
differences,  if  any,  between  the  records  at  the  beginning  and  end  of  the 
experiment.  The  influence  of  muscular  activity  and,  in  some  cases, 
that  of  food  obtain  in  these  measurements.  For  the  experiments  the 
child  was  placed  in  the  chamber  and  instructed  to  remain  quiet.  No 
observations  were  made  until  this  quiet  condition  had  been  secured. 
During  the  experiment  of  an  hour  or  more,  and  with  conditions  of 
reasonably  complete  muscular  repose  and  frequently  sleep,  there  would 
normally  be  a  definite  fall  in  temperature.  On  the  other  hand,  the 
experiments  were  at  times  continued  until  the  child  awoke  or  became 
restless;  this  activity  would  make  it  necessary  to  discontinue  the 
experiment,  since  the  main  object  was  a  study  of  the  basal  metabolism. 
Under  these  conditions,  the  activity  at  the  end  of  the  experiment 
would  tend  to  increase  the  body  temperature  and  the  second  record 
would  thus  be  higher. 

A  study  of  all  the  experiments  in  which  records  were  obtained  at 
the  beginning  and  end  shows  that  in  the  189  experiments  with  boys 
used  in  the  mini  mum-metabolism  table  (see  table  27,  page  116),  there 
was  no  rise  or  fall  in  19  experiments,  an  average  rise  of  0.55°  F.  in 
52  cases,  and  an  average  fall  of  0.71°  F.  in  118  cases.  Thus,  with  the 
boys,  10  per  cent  of  these  189  experiments  showed  no  change  in  body 
temperature,  27.5  per  cent  showed  a  rise,  and  62.5  per  cent  a  fall, 
the  range  in  variation  being  from  +0.55°  F.  to  -0.71°  F.  In  the  214 
experiments  with  girls  used  in  the  mmimum-metabolism  table  (see 
table  28,  page  120),  there  was  no  change  in  temperature  in  24  experi- 
ments, an  average  rise  of  0.49°  F.  hi  51  experiments,  and  an  average 
fall  of  0.71°  F.  in  139  experiments.  In  these  experiments  with  girls, 
therefore,  there  was  no  change  in  11.2  per  cent,  a  rise  in  23.8  per 


INFLUENCE    OF   FOOD    ON   METABOLISM.  89 

cent,  and  a  fall  in  65  per  cent,  with  a  range  in  average  variation  from 
+0.49°  F.  to  -0.71°  F. 

While  in  this  comparison  only  those  experiments  were  used  which 
were  included  in  the  minimum  metabolism  tables,  but  little  if  any 
difference  in  the  results  was  found  when  all  the  measurements  were 
compared.  It  may  be  safely  concluded,  therefore,  that  there  was  a 
tendency  in  general  for  the  temperature  to  fall  during  the  experiments 
and  that  this  was  independent  of  sex.  The  body  temperatures  were 
usually  below  100°  F.  and,  if  100°  F.  at  the  beginning,  generally  fell 
below  at  the  end.  This  tendency  to  a  fall  was  undoubtedly  due  to  the 
contrast  between  the  quiet  and  muscular  relaxation  in  the  experi- 
mental period  and  the  pre-experimental  activity.  This  interpretation 
of  the  change  is  made  the  more  probable  by  the  fact  that,  from  an 
inspection  of  the  records  showing  a  rise  at  the  end  of  the  experiment, 
it  appears  that  in  the  majority  of  cases  the  increase  hi  body  tempera- 
ture was  accompanied  by  a  considerable  degree  of  activity  in  the  last 
period  of  the  experiment. 

In  the  majority  of  experiments  with  children  older  than  2  years, 
the  temperature  measurement  was  made  only  at  the  end  of  the  experi- 
ment. Accordingly,  this  comparison  of  the  measurements  before  and 
after  the  experiment  applies  more  particularly  to  children  2  years  old 
or  younger,  although  some  20  boys  and  5  girls  are  included  hi  the  data 
compared  who  were  over  2  years  of  age.  In  conclusion,  it  may  be 
said  that  these  observations  on  the  body  temperature  of  young  children 
indicate,  on  the  whole,  that  during  the  first  two  years  of  life  there  is  a 
definite  tendency  for  the  rectal  temperature  to  increase  slightly,  with  a 
maximum  at  about  2  years  of  age.  Thereafter  the  body  temperature 
slowly  falls,  with  no  perceptible  general  trend  apparent  from  5  to  13 
years  of  age.  These  variations  hi  temperature  show  strikingly  the 
desirability  of  more  extensive  studies  of  the  diurnal  range  by  means  of 
some  more  sensitive  measurement,  such  as  a  bolometric  or  thermo- 
electric method,  with  continuous  or  semi-continuous  registration. 

INFLUENCE  OF  FOOD  ON  METABOLISM. 

As  outlined  in  a  previous  section  (see  page  30),  with  the  youngest 
children  it  was  not  possible  to  obtain  ideal  conditions  for  measuring 
the  basal  metabolism,  i.  e.,  complete  muscular  repose  and  with  no  food 
in  the  alimentary  tract,  or  the  "post-absorptive"  condition.  With 
adults  the  post-absorptive  condition  is  usually  not  secured  until  12 
hours  after  an  ordinary  meal  and  the  maximum  increase  following  a 
protein-rich  meal  may  be  as  high  as  40  to  50  per  cent  for  a  short  tune, 
with  its  effect  possibly  continued  even  longer  than  12  hours.  With 
the  children  observed  in  this  study,  excessively  large  meals  were  not 
the  rule,  the  last  meal  before  the  observations  with  the  respiration 
apparatus  being  purposely  considerably  reduced. 


90   METABOLISM  AND  GKOWTH  FROM  BIRTH  TO  PUBERTY. 

A  careful  control  of  the  muscular  activity  was  secured  through 
graphic  records.  With  the  youngest  children,  and  especially  the 
infants,  however,  it  was  not  possible  to  obtain  the  required  degree  of 
muscular  repose  when  there  was  no  food  in  the  stomach,  because  the 
want  of  food  caused  restlessness  and  frequently  crying.  In  recognition 
of  this  difficulty,  it  was  necessary  to  compromise  by  supplying  as 
small  an  amount  of  food  as  would  produce  comfort  and  consequent 
muscular  repose.  This  amount  of  food,  even  though  small,  inevitably 
influenced  the  metabolism.  When  older  children  were  studied,  it 
was  possible  to  postpone  the  observations  after  a  meal  for  a  longer 
period  of  time,  even  for  4  or  5  hours.  Accordingly,  in  the  subsequent 
analysis  of  the  metabolism  data  for  the  children  of  various  ages,  it 
must  be  remembered  that  as  the  age  of  the  children  increases  the 
influence  of  the  ingestion  of  food  decreases  correspondingly.  The 
basal  metabolism  of  children  under  2  years  of  age  can  thus  be  com- 
pared with  that  of  older  children  only  on  the  distinct  understanding 
that  the  values  for  the  basal  metabolism  for  the  younger  children  are 
higher  than  they  normally  would  be,  owing  to  the  influence  of  food. 

The  quantitative  measurement  of  the  influence  of  the  ingestion  of 
food  upon  the  metabolism  of  infants  should  be  given  special  study, 
such  as  has  been  done  for  adults  in  a  previous  publication  from  this 
laboratory.1  Certain  more  or  less  fragmentary  evidence  has,  however, 
been  accumulated  in  the  present  research  with  children,  in  part  by 
design  and  in  part  by  accident.  With  several  of  the  children,  a  pro- 
longed series  of  observations  was  made  after  food  had  been  taken, 
some  of  these  continuing  9  or  10  hours  without  interruption.  The 
results  of  these  observations  give  some  information  as  to  the  possible 
influence  of  food.  Here  again  we  find  a  difficulty  in  interpretation  in 
that  the  somewhat  subtle  influence  of  food  is  profoundly  affected  by  a 
change  in  the  activity;  hence  only  periods  of  comparable  muscular 
activity,  or  preferably  muscular  repose,  can  legitimately  be  used  to 
determine  the  influence  of  food  upon  the  metabolism.  That  is,  it  must 
be  assured  that  the  increase  in  the  metabolism  after  food  is  not  due 
to  muscular  activity  before  assuming  it  is  due  to  the  stimulus  of  food. 

The  data  contributing  to  a  study  of  this  problem  are  brought  to- 
gether in  table  23,  in  the  order  of  increasing  age.  Unfortunately, 
long  observations  during  which  the  minimum  metabolism  after  feeding 
has  been  measured  were  made  only  with  relatively  young  children, 
the  oldest  being  but  13|  months  old.  This  table  gives  not  only  the 
age  and  weight  of  the  individual  children,  but  also  the  energy  content 
of  the  food,  the  time  of  feeding,  the  interval  between  the  food  and  the 
end  of  the  period  of  observation,  the  heat  produced  on  the  basis  of 
24  hours,  the  pulse-rate,  and  the  relative  activity.  The  time  when 
presumably  basal  metabolism  was  reached  is  indicated  by  an  italiciza- 
tion  of  the  lowest  value  for  heat. 

1  Benedict  and  Carpenter,  Carnegie  Inst.  Wash.  Pub.  No.  261,  1918. 


INFLUENCE    OF   FOOD    ON   METABOLISM. 


91 


TABLE  23. — Heat  production  of  infants  after  food. 


Subject  No.,  age,  and  weight. 

Date. 

En- 
ergy 
of 
food 

Time  of  feeding. 

Inter- 
val be- 
tween 
food 
and 
end  of 
period 

Heat  produced  | 
per  24  hours.1 

Pulse-rate. 

Rela- 
tive 
ac- 
tivity.* 

1916 

cals. 

h.  m. 

cals. 

127  (2|  mos.;  5.03  kilos)  

Apr.  20-21 

60 

6h48mto   7h07mp.m. 

1  21 

287 

117 

I 

1  56 

301 

119 

II 

2  32 

286 

118 

I 

3     7 

287 

116 

I 

3  44 

299    112    III(?) 

4  20 

281    114!    II 

4  57 

255 

115   III(?) 

5  31 

267 

115     II 

Apr.  21 

90 

1  12  to   1  21  a.m. 

1  11 

291 

121)    II 

90 

6  42  to   6  50  a.m. 

1  41 

336 

117 

III(?) 

100 

9  28  to   9  42   a.m. 

1  18 

280 

115 

II(?) 

60 

12  32  to  12  47  p.m. 

40 

322 

119 

III(?) 

115  (4|  mos.;  5.86  kilos)  

Mar.  25 

80 

5  40  to  548  p.m.    1  28 

348 

137 

II 

2  10 

335 

131 

I 

2  49 

328 

125 

II 

3  32 

312 

125 

Mar.  25-26 

110 

9  54  to  10  35  p.m. 

1     9 

362 

137 

1  44 

312 

128 

2  27 

342 

126 

I 

3  11 

296 

124 

I 

119  (6  mos.;  7.21  kilos)  

Apr.  15-16 

80 

7  08  to  7  14  p.m. 

1     8 

403 

107 

1  58 

397 

115 

2  39 

397 

118 

3  27 

391 

115 

III(?) 

4  41 

392 

117 

Ill 

5  18 

373 

122 

II 

5  41 

369 

122 

III(?) 

Apr.  16 

210 

2  06  to  2  26   a.m. 

1  23 

422 

119 

I 

1  50 

477 

129 

II 

2  35 

457 

132 

H(?) 

3    2 

437 

125 

K?) 

140  (6  mos.;  6.38  kilos)  

Apr.  16-17 

70 

6  24  to  6  38  p.m. 

1  24 

380 

113 

I 

1  56 

356 

112 

I 

2  30 

405 

114 

I 

2  58 

390 

114 

II 

5    3 

356 

109 

II 

5  48 

353 

115 

III 

6  13 

337 

109 

IK?) 

Apr.  17 

170 

1  38  to   1  58  a.m. 

1     0 

364 

119 

II 

1  31 

400 

120 

II 

2     7 

359 

112 

II 

3  10 

373 

108 

II 

123  (6imos.;  6.09  kilos)  .... 

Apr.  17-18 

60 

6  45  to   7  04  p.m. 

1  11 

334 

118 

K?) 

1  42 

359 

124 

I 

2    9 

378 

124 

II 

2  35 

361 

125 

I 

3     7 

363 

123 

II 

3  39 

349 

121 

I 

4     5 

353 

123 

II 

The  lowest  value,  presumably  the  basal  value,  is  italicized  in  each  series  of  observations 
The  designations  for  the  activity  are  given  the  following  values:  I,  very  quiet,  probably  asleep; 
II,   slight   movements,   few  in   number;     III,   some  activity,   but  generally  quiet.     The 
method  of  estimating  the  activity  is  described  by  Benedict  and  Talbot,  Carnegie  Inst. 
Wash.  Pub.  No.  201,  1914,  p.  136. 


92   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


TABLE  23. — Heat  production  of  infants  after  food — Continued. 


Subject  No.,  age  and  weight. 

Date. 

En- 
ergy 
of 
food. 

Time  of  feeding. 

Inter- 
val be- 
tween 
food 
and 
end  of 
period. 

IHeat  produced 
per  24  hours.1 

Pulse-rate. 

Rela- 
tive 
ac- 
tivity.1 

1916 

cals. 

h.m. 

cals. 

123  (e^mos.;  6.09  kilos)  
(Continued.) 

Apr.  17-18 

60 

6h45mto   7h04mp.m. 

4  35 
5  13 
6     9 

330 
335 
333 

118 
116 
119 

I 
II 
II 

7  12 

328   118    III 

8     1 

322    120       I 

9     8 

812 

1241     II(?) 

131  (6imos.;  5.76  kilos)  

Apr.  19-20 

50 

6  46  to   6  51  p.m. 

1     8 
1  43 

331 
354 

120,       I 
129       I 

2  13 

354 

12l!       I 

2  45 

371 

130|     II 

2  53 

329 

127 

I 

3  46 

340 

128 

H(?) 

4  16 

315 

129 

II 

4  47 

318 

130 

I 

5  59 

342 

130 

I 

7    8 

328 

126 

I 

9     7 

326 

141 

I(?) 

9  36 

391  |143 

I 

Apr.  20 

100 

5  56  to   6  02   a.m 

59 

373  J137      II 

1  48 

392    131      II 

2  17 

372    118       I 

90 

8  59  to   9  07   a.m 

1  27 

299   120i     II 

2  25 

328  !ll9       I 

3  21 

337   118       I 

100 

3  51  to  3  57  p.m 

1  59 

325    114       I 

3     6 

323    122      II 

139  (6jmos.;  6.11  kilos).  ... 

Feb.  19 

130 

5  35  to  5  44  p.m 

1  59 

350 

122 

II 

2  50 

363 

123 

I 

3  42 

328 

125 

I 

Feb.  19-20 

80 

9  35  to  9  55  p.m 

1  13 

393 

129 

II(?) 

2     4 

371  |129 

I 

2  52 

354 

126 

II 

3  41 

342 

125 

I 

4  30 

366    125      II 

5  50 

332  |127    III 

6  22 

325  |124        I 

7  19 

345    125:     II(?) 

136(7imos.;  9.08  kilos)  ... 

Mar.  11-12 

50 

5  48  to   6  08  p.m 

1  31 

500   106      II 

2  16 
3  10 

505    109      II 
471    1061     II 

4     4 

463    104      II(?) 

4  57 

461    103 

IK?) 

5  51 

472    106 

UK?) 

6  30 

481 

106     II 

Mar.  12 

230 

12  45  to   1  07   a.m 

1  15 

501 

109       I 

1  51 

520  IllO    III 

148(8|mos.;  8.87  kilos)  ... 

Feb.  26 

170 

4  55  to  5  10  p.m 

2  28 

493    108       I 

3  13 

475    107J       I 

3  58 

481    106]     II 

1  The  lowest  value,  presumably  the  basal  value,  is  italicized  in  each  series  of  observations. 

1  The  designations  for  the  activity  are  given  the  following  values:  I,  very  quiet,  probably  asleep; 
II,  slight  movements,  few  in  number;  III,  some  activity,  but  generally  quiet.  The 
method  of  estimating  the  activity  is  described  by  Benedict  and  Talbot,  Carnegie  Inst. 
Wash.  Pub.  No.  201,  1914,  p.  136. 


INFLUENCE   OF   FOOD    ON   METABOLISM. 


93 


TABLE  23. — Heat  production  of  infants  after  food — Continued. 


Inter- 

-. „ 

Subject  No.,  age,  and  weight. 

Date. 

En- 
ergy 
of 
food. 

Time  of  feeding. 

val  be- 
tween 
food 
and 
end  of 

[eat  produce 
>er  24  hours 

Pulse-rate. 

Rela- 
tive 
ac- 
tivity.* 

period. 

w  ~ 

1916 

cols. 

h.  m. 

cols. 

184  (8|  mos.  ;  887  kilos)  .... 

Feb.  26 

170 

4h55mto  5h10mp.m. 

4  47 

467   108|     II 

6  13 

470   114]  III 

Feb.  26-27 

130 

11  30  toll  42  p.m. 

1  24 

511  il!7 

I 

2  14 

506  !l!8 

I 

2  52 

516    113 

II 

3  34 

478 

114 

I 

4     5 

522 

112 

II 

4  46 

479   115 

II 

5  21 

502    117 

I 

171  (13£  mos.;  8.70  kilos)  .  .  . 

Mar.    4-5 

f310 
1170 

4  00  to  4  10p.m.} 
5  45  to  6  00  p.m.  ) 

2  27 

629 

136 

II 

2  57 

608   134 

I 

3  29 

647    133 

II 

4  13 

616 

132 

II(?) 

4  53 

602 

131 

II 

5  44 

584   128 

III 

6  45 

608    130 

IK?) 

8  37 

579 

132 

I 

9  11 

645 

129 

II 

10    4 

570 

126 

I 

10  51 

554 

129 

I 

11  17 

555 

131 

II 

1  The  lowest  value,  presumably  the  basal  value,  is  italicized  in  each  series  of  observations. 

1  The  designations  for  the  activity  are  given  the  following  values:  I,  very  quiet,  probably  asleep; 
II,  slight  movements,  few  in  number;  III,  some  activity,  but  generally  quiet.  The 
method  of  estimating  the  activity  is  described  by  Benedict  and  Talbot,  Carnegie  Inst. 
Wash.  Pub.  No.  201,  1914,  p.  136. 

The  basal  metabolism  of  a  child,  like  that  of  an  adult,  is  not  neces- 
sarily a  fixed  factor;  hence  it  is  unjustifiable  to  use  a  basal  value 
obtained  on  one  day  for  comparison  with  the  metabolism  after  food 
on  another  day  to  determine  the  effect  of  the  food.  The  question  of 
the  selection  of  a  suitable  basal  value  for  experiments  in  such  studies 
has  already  been  exhaustively  discussed  in  a  previous  publication.1 
It  was  there  pointed  out  that  only  basal  values  obtained  on  the  same 
day  were  legitimate  for  comparison  with  the  metabolism  after  food, 
and  also  that  the  metabolism  after  one  or  two  days  of  fast  was  not  a 
true  basal  value;  also  that  for  ideal  comparisons  the  basal  value 
without  food  should  first  be  obtained  and  the  metabolism  with  the 
superimposed  factor  of  food  studied  immediately  thereafter. 

The  most  extensive  series  of  observations  after  food  were  made  with 
the  three  children  Nos.  123,  131,  and  171.  Of  these,  the  series  with 
the  oldest  child  No.  171,  on  March  4-5,  1916,  was  the  longest  con- 
tinued, observations  being  made  for  over  11  hours  after  the  food  had 

1  Benedict  and  Carpenter,  Carnegie  Inst.  Wash.  Pub.  No.  261,  1918,  p.  47. 


94   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

been  taken.  Here,  2|  hours  after  food,  the  metabolism  was  629 
calories,  rising  an  hour  later  to  647  calories,  thereafter  falling  continu- 
ously until  two  minimum  periods  of  545  and  555  calories  are  found  at 
9  and  11  hours,  respectively,  after  the  food  had  been  taken.  If  we 
consider  the  absolute  minimum  of  545  calories  as  basal,  then  the  647 
calories,  or  the  maximum  heat  production,  represents  an  increase  of 
102  calories,  or  about  20  per  cent,  due  to  the  influence  of  food.  But 
this  increase  is  relatively  soon  after  feeding.  The  pulse-rate  likewise 
shows  a  distinct  tendency  to  fall  off  after  the  first  rise  due  to  the  taking 
of  food.  The  average  value  of  550  calories,  which  may  be  taken  as 
the  basal  value,  was  determined,  roughly  speaking,  10  hours  after  the 
last  meal. 

An  examination  of  the  chart  for  No.  171  (see  fig.  16,  page  124)  shows 
that  at  the  age  of  13|  months  there  is  a  decided  break  in  the  line  for 
the  total  calories,  indicating  a  fairly  low  value  at  that  time.  The 
period  of  observation  is  considerably  longer  than  that  for  most  of  the 
children  in  the  series.  It  is  therefore  quite  likely  that,  had  the  experi- 
ment been  shorter,  the  point  would  more  closely  correspond  to  the 
general  trend  of  the  curve.  But  great  stress  should  not  be  laid  upon 
individual  variations  from  day  to  day  or  from  period  to  period. 

On  April  17-18,  1916,  a  long  experiment  was  made  with  the  infant 
No.  123,  in  which  the  child  took  food  containing  but  60  calories  of 
energy.  The  metabolism  was  thereafter  measured  continuously  for 
over  9  hours.  While  the  absolute  minimum  value  of  312  calories  was 
found  in  the  last  period,  the  values  for  the  last  2  hours  indicate  relative 
constancy.  The  maximum  of  378  calories,  which  occurred  2  hours  and 
9  minutes  after  food,  is  equivalent  to  an  increase  of  66  calories  above 
the  minimum,  or,  roughly  speaking,  20  per  cent.  The  pulse-rate  shows 
a  general  tendency  to  decrease  after  the  maximum  metabolism  is 
reached,  although  the  minimum  pulse-rate  is  not  coincidental  with  the 
minimum  metabolism. 

The  series  of  observations  with  No.  131  continued  for  9|  hours  after 
food.  The  amount  of  food  taken  was  insignificant  in  quantity  and 
energy  content,  and  the  minimum  value  actually  appeared  about  4^ 
hours  afterwards.  The  maximum  value  (391  calories)  was  found  9^ 
hours  after  food,  or  some  5  hours  after  the  minimum  value  appeared. 
The  great  increase  in  the  pulse-rate  is  wholly  inexplicable,  for  the 
kymograph  records  indicate  activities  of  but  I  and  II,  and  the  subject 
was  presumably  asleep.  We  have  no  explanation  for  these  unusual 
figures. 

With  the  other  children,  shorter  observations  were  the  rule  after 
food.  With  No.  127,  on  April  20-21,  1916,  five  feedings  were  given, 
the  observations  after  the  first  feeding  continuing  without  break  for 
5  hours  and  31  minutes.  The  absolute  minimum  of  255  calories  was 
found  about  5  hours  after  food.  As  the  maximum  value,  which  was 


INFLUENCE   OF   FOOD    ON   METABOLISM.  95 

obtained  1  hour  41  minutes  after  the  third  feeding,  was  336  calories, 
there  was  a  maximum  rise  of  81  calories,  or  approximately  30  per  cent. 
Singularly  enough,  there  was  no  marked  change  in  the  pulse-rate,  the 
maximum  increase  being  but  a  few  beats. 

The  series  of  observations  with  No.  115  after  the  two  feedings  agree 
very  satisfactorily,  although  the  question  of  the  actual  basal  value  is 
in  doubt,  since  this  must  be  taken  as  but  3  hours  and  11  minutes  after 
the  second  feeding.  The  total  increase  on  this  basis  is,  therefore,  66 
calories,  or  about  22  per  cent  above  basal. 

The  observations  with  the  other  children  were  approximately  3  to  6 
hours  in  length  and  usually  indicate  the  minimum  at  the  end  of  the 
period  of  observation,  with  maximum  increases  shortly  after  food  was 
taken,  these  corresponding  to  not  far  from  20  to  30  per  cent  with  most 
of  the  children.  Of  special  interest  with  No.  119  is  the  fact  that  in 
the  second  feeding  the  energy  in  the  food  was  almost  three  times  that 
in  the  first  feeding,  and  under  these  conditions  a  distinctly  higher 
metabolism  was  noted.  If  we  accept  the  basal  value  as  369  calories, 
which  was  obtained  5  hours  and  41  minutes  after  the  feeding  of  80 
calories  in  breast  milk,  we  find  an  increase  of  108  calories  1  hour  and 
50  minutes  after  the  second  feeding  of  breast  milk  with  an  energy  con- 
tent of  210  calories.  This  increase  after  the  second  feeding  corre- 
sponds to  about  29  per  cent,  as  compared  with  the  maximum  increase 
of  34  calories,  or  9  per  cent,  1  hour  and  8  minutes  after  the  first  feeding 
of  a  very  much  smaller  amount  of  breast  milk.  With  No.  140,  who 
was  the  same  age  as  No.  119,  the  energy  content  of  the  milk  in  the 
first  feeding  was  70  calories,  while  that  of  the  second  feeding  was  170 
calories.  Here  the  increase  due  to  the  larger  amount  of  milk  was 
very  slight,  if  any.  It  is  also  worthy  of  note  that  No.  136,  after 
a  second  feeding,  showed  a  maximum  heat  production  no  greater 
than  that  found  after  the  first  feeding,  although  the  second  feed- 
ing had  an  energy  content  four  or  five  tunes  larger  than  that  of  the 
first. 

From  an  inspection  of  the  data  in  table  23  it  is  clear  that  in  most 
instances  the  absolute  minimum  values  were  not  found  before  8  to  9 
hours  after  the  last  food.  In  nearly  every  one  of  the  long  series  of 
observations  the  minimum  values  occur  at  or  near  the  end.  An 
exception  to  this  is  No.  131  in  the  observations  on  April  19-20,  when 
approximately  the  minimum  was  found  4|  hours  after  the  food.  The 
energy  content  of  the  food  in  this  case  was,  however,  but  50  calories. 
Numerically  the  same  conditions  hold  with  regard  to  the  observations 
on  March  11-12,  1916,  with  No.  136.  It  is  probable,  therefore,  that 
with  as  small  an  amount  of  food  as  2  or  3  ounces  of  breast  milk,  with 
an  energy  content  of  approximately  50  calories,  the  metabolism  is 
nearly  basal  at  the  end  of  4  hours.  With  larger  amounts  of  food  the 
stimulating  effect  may  persist  for  9  or  10  hours. 


96   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

It  has  been  currently  believed  that  the  influence  of  food  is  con- 
siderably smaller  with  children  than  with  adults  and  that  the  protein 
utilized  for  growth  does  not  participate  in  the  stimulating  action 
formerly  termed  "specific  dynamic  action."  Frankly,  we  were  misled 
in  some  of  our  earlier  observations  by  this  belief,  but  the  evidence 
here  presented  certainly  gives  no  indication  of  a  material  lessening  in 
the  influence  of  food.  Indeed,  the  general  conclusion  to  be  drawn 
from  these  data  is  that  the  influence  of  food  upon  the  metabolism  of 
infants  is  wholly  comparable  to  that  noted  with  adults.  This  renders 
all  the  more  potent  our  contention  that  basal  metabolism  measure- 
ments with  young  children  are  not  ideal  in  the  commonly  accepted 
definition  of  the  term  basal  as  applied  to  adults,  since  they  are  not 
made  under  conditions  which  preclude  the  stimulating  action  of  food. 

A  rough  assumption  may  be  made  that  the  basal  metabolism  as 
measured  in  our  series  of  experiments  is,  in  practically  every  instance, 
from  8  to  15  per  cent  higher  than  the  true  basal.  This  fact  must  be 
clearly  recognized  in  the  subsequent  analysis  of  the  general  trend  of 
the  metabolism  for  children  of  varying  ages.  In  the  light  of  the 
variations  shown  in  table  23,  however,  the  direct  application  to  our 
data  of  this  percentage  correction  is  not  justifiable.  Consequently, 
until  further  observations  are  made  upon  the  quantitative  effects  of 
food  on  the  metabolism  of  children,  one  can  only  emphasize  the  fact 
that  the  younger  the  child  is,  the  greater  is  the  deviation  from  basal 
towards  a  higher  measurement  of  the  metabolism. 

It  is  a  matter  of  regret  that  the  influence  of  food  was  not  studied 
with  older  children,  but  since  it  has  been  made  clear  that  the  basal 
values  are  too  high,  especially  with  the  younger  children,  it  is  not 
impossible  that  these  high  values  may,  when  corrected,  equalize  the 
values  for  heat  production  per  square  meter  and  bring  them  more  in 
accordance  with  those  found  with  adults.  On  the  other  hand,  it 
would  appear  that  if  a  correction  were  applied  for  children  6  months 
and  under,  it  would  only  further  distort  the  comparison  curves  for 
the  metabolism.  (See  discussion  of  these  curves  in  a  subsequent 
section,  page  176.)  Final  treatment  of  these  curves,  i.  e.,  in  com- 
parisons of  children  ranging  in  age  from  birth  to  puberty,  and  par- 
ticularly in  comparisons  of  children  with  adults,  must  be  subject  to 
the  possibility  of  a  correction  to  obtain  the  true  basal.  On  the  one 
hand,  there  will  be  a  distinct  objection  to  establishing  a  so-called 
correction  on  relatively  few  long  experiments;  on  the  other  hand, 
there  will  be  a  distinct  objection  fco  comparing  true  basal  values 
with  the  basal  values  of  youth  which  are  too  high  as  a  result  of  previous 
food.  Except  in  cases  of  great  weakness  and  probably  disease,  no 
metabolism  values  for  youth  may  be  considered  as  under  basal,  the 
tendency  always  being  for  such  values  to  be  above  rather  than  below 
true  basal. 


ELEMENT   OF   NOVELTY   IN   MEASUREMENTS   OF   METABOLISM.      97 

Aside  from  the  physical  difficulties  met  with  in  attempting  to  secure 
measurements  of  the  metabolism  of  children  under  true  basal  condi- 
tions, we  have  to  deal  with  the  possibility  of  an  incipient  acidosis. 
With  adults,  complete  fasting  soon  produces  a  reduction  in  the  store 
of  glycogen  and  shortly  thereafter  acidosis  sets  in.  The  earlier 
experiments  of  Schlossmann  and  Murschhauser1  seemed  to  show  that 
this  acidosis  appeared  much  earlier  with  children  than  with  adults. 
Experience  in  this  laboratory,  both  with  a  fasting  man2  and  with 
diabetics,3  indicates  strongly  that  the  metabolism  is  noticeably  stimu- 
lated by  acidosis.  As  has  been  shown  in  other  publications,  it  becomes 
a  serious  problem  to  decide  upon  the  exact  point  when  the  stimulating 
effect  of  food  ceases  and  the  stimulus  of  acidosis  begins.  Even  with 
adults  this  point  has  never  been  sharply  denned,  although  from  the 
general  trend  of  metabolism  during  long  experiments  it  appears  that  a 
minimum  is  reached  not  far  from  10  to  12  hours  after  the  last  food  is 
taken,  unless  the  last  meal  was  particularly  rich  in  protein.  Since 
one  may  designate  the  measured  metabolism  of  these  younger  children 
only  as  approximating  basal,  comparisons  between  these  values  and 
true  basal  values  for  adults  must  be  made  with  extreme  caution. 

THE  ELEMENT  OF  NOVELTY  IN  MEASUREMENTS  OF 
METABOLISM. 

Throughout  our  entire  series  of  experiments  we  were  frequently  con- 
fronted with  the  question  as  to  how  much  of  a  role  the  element  of 
novelty  played  in  the  determination  of  metabolism.  Naturally,  when 
the  children  went  into  the  respiration  chamber  for  the  first  experi- 
ment, their  attitude  toward  the  apparatus  was  somewhat  different 
from  that  in  the  second  experiment.  While  every  effort  was  made  to 
accustom  the  children  to  seeing  the  apparatus  in  working  order  and 
to  assure  them  that  there  was  nothing  distressing  or  uncomfortable 
in  the  experiments,  the  novelty  of  being  placed  inside  the  respiration 
chamber  might  conceivably  affect  the  basal  metabolism;  hence  values 
secured  on  the  first  day  might  be  looked  upon  as  aberrant. 

For  a  strict  comparison  of  the  results  obtained  under  the  two  con- 
ditions, it  is  important  in  the  first  place  that  the  two  days  be  reason- 
ably close  together,  so  as  to  eliminate  the  factors  of  age  and  weight. 
Secondly,  the  periods  for  comparison  must  be  of  the  lowest  order  of 
activity;  that  is,  the  child  should  preferably  be  in  complete  repose  in 
both  periods.  After  a  careful  scrutiny  of  our  data,  we  have  selected  a 
number  of  experiments  with  children  of  both  sexes  and  varying  ages, 
which  give  suitable  data  for  such  comparison.  These  are  brought 
together  in  table  24,  which  shows  the  heat  production  on  the  24-hour 

1  Schlossmann  and  Murschhauser,  Biochem.  Zeitschr.,  1913,  56,  p.  396. 

2  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  203,  1915,  p.  365. 

3  Benedict  and  Joslin,  Carnegie  Inst.  Wash.  Pub.  No.  176,  1912,  pp.  125  and  134. 


98   METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


TABLE  24. — Comparison  of  metabolism  and  pulse^rate  in  first  and  second 
experiments  with  children. 


Heat  (computed) 

Pulse- 

per  24  hrs. 

rate. 

Relative 

Subject  No. 

Age. 

Date. 

No  of 

activity. 

Amt. 

Diff. 

beats. 

Diff. 

Boys: 

yrs.  mos. 

cols. 

cals. 

192  

5      7 

May  21,  1919 

866 

90 

11,1 

May  22,  1919 

962 

+  96 

89 

-  1 

I,  II 

194  

5      9 

Mar.  19,  1918 

876 

85 

1,1 

Mar.  22,  1918 

830 

-  46 

87 

+  2 

I,  I 

204  

7      2 

Mar.  29,  1919 

999 

81 

1,11 

Apr.     1,  1919 

908 

-  91 

86 

+  5 

1,1 

209  

7     10 

Mar.    1,  1918 

1,094 

83 

I,  I,  II 

Mar.  18,  1918 

1,096 

+     2 

74 

-  9 

I,  I,  II 

228  

9     10 

Feb.     5,  1919 

1,241 

85 

I,  II,  I 

Feb.     6,  1919 

1,215 

-  26 

75 

-10 

11,11 

235  

10      7 

Feb.  19,  1919 

1,063 

93 

1,1,  I 

Feb.  20,  1919 

1,056 

-     7 

84 

-  9 

I,  I,  I 

242  

11 

Nov.  25,  1918 

1,215 

87 

II   II 

Nov.  27,  1918 

1,186 

-  29 

88 

+  1 

I  II 

246  

11       6 

Feb.     6,  1919 

1,320 

70 

I  II 

Feb.     7,  1919 

1,314 

-     6 

64 

-  6 

,1 

250  

12      2 

June  24,  1918 

1,355 

71 

I,  II   II 

June  27,  1918 

1,211 

-144 

61 

-10 

I,  II   II 

256  

12      9 

Feb.  20,  1918 

1,365 

87 

I  II 

Feb.  23,  1918 

1,290 

-  75 

72 

-15 

II  II 

258  

13      8 

Apr.  17,  1919 

1,529 

66 

I.I 

Apr.  18,  1919 

1,504 

-  25 

62 

-  4 

I,  II 

259  

14       1 

May    6,  1918 

1,260 

78 

I,  I 

May    8,  1918 

1,220 

-  40 

66 

-12 

1,1 

260.....'. 

15       . 

May     1,  1919 

1,417 

74 

I,  I,  II 

May    6,  1919 

1,431 

+  14 

71 

-  3 

1,1,1 

Average: 

1st  day 

1,200 

81 

2d  day 

1,171 

-  29 

75 

-  6 

Girls: 

178  

2     11 

Mar.  19,  1918 

572 

84 

I,  I,  I,  I 

Mar.  21,  1918 

574 

+     2 

91 

+  7 

1,1,1 

189  

5      3 

Feb.  20,  1919 

875 

80 

I,  I 

Feb.  21,  1919 

831 

-  44 

78 

-  2 

II,  I 

220  

9       1 

Apr.  11,  1918 

1,031 

101 

II,  II 

Apr.   12,  1918 

996 

-  35 

97 

-  4 

11,11 

225  

9      5 

Jan.   22,  1919 

954 

88 

1,1,1 

Jan.   23,  1919 

957 

+     3 

82 

-  6 

I,  I,  II 

238  

10     10 

Apr.  26,  1919 

987 

89 

III 

May    3,  1919 

1,103 

+116 

81 

-  8 

1,1,1 

251  

12      2 

Mar.    8,  1919 

1,027 

79 

I,  I,  I 

Mar.  11,  1919 

l!o42 

+  15 

76 

-  3 

1,1,  I 

Average: 

1st  day  .  . 

908 

87 

2d  day 

917 

+     9 

84 

—  3 

Gen.  average: 

1st  day  .  . 

1,108 

83 

2dday... 

l!o91 

-  17 

78 

-  5 

basis  for  the  first  and  second  days  of  observation,  the  pulse-rate,  and 
(to  indicate  the  degree  of  repose)  the  activity  as  estimated  from  the 
kymograph  records.  To  indicate  any  variations  due  to  sex,  the  data 
have  been  grouped  separately  for  boys  and  girls. 


ELEMENT   OF   NOVELTY   IN   MEASUREMENTS   OF   METABOLISM.      99 

With  the  majority  of  the  subjects  the  observations  were  made  on 
succeeding  days,  and  with  few  exceptions  not  more  than  three  days 
apart.  These  exceptions  were  Nos.  209,  238,  and  260,  with  whom 
the  observations  were  made  17,  7,  and  5  days  apart,  respectively. 
The  agreement  in  the  values  for  the  heat  production  for  the  two  days 
is,  in  most  cases,  reasonably  close.  The  results  for  the  second  day  are, 
in  many  instances,  lower  than  those  for  the  first  day,  but  the  reverse 
is  likewise  true,  so  that,  taking  the  plus  and  minus  signs  into  considera- 
tion, one  may  state  that  the  general  average  difference  between  the 
first  and  second  day  for  all  of  the  children  is  but  — 17  calories.  Bearing 
in  mind  the  difficulty  of  estimating  relative  activity  from  day  to  day, 
especially  at  the  lower  grades  of  activity,  we  find  that  the  records  of 
the  relative  activity  in  the  last  column  of  table  24  indicate  that  the 
average  activity  on  the  two  days  was  equal. 

Of  special  significance,  however,  is  the  pulse-rate,  both  when  com- 
pared for  the  first  and  second  days  of  experimenting  and  particularly 
when  compared  with  the  value  for  the  total  heat  production.  In  the 
majority  of  instances  the  pulse-rate  is  lower  on  the  second  day  than 
on  the  first  day,  the  average  of  the  values  for  all  of  the  children  on  the 
second  day  being  78  beats  per  minute  as  compared  with  83  beats  on 
the  first  day.  In  many  cases  the  pulse-rate  is  notably  lower  on  the 
second  day.  The  influence  of  "training,"  so  to  speak,  is  thus  definitely 
towards  a  decidedly  lower  pulse-rate.  A  few  instances  of  a  higher 
pulse-rate  on  the  second  day  occur,  these  being  found  with  three 
boys,  Nos.  194,  204,  and  242,  and  with  one  girl,  No.  178.  The  largest 
change  is  with  the  boy  No.  256,  whose  pulse-rate  fell  from  87  to  72, 
or  a  total  change  of  15  beats.  Changes  of  9  or  10  beats  are  noted  in 
several  cases,  especially  with  the  boys.  With  these  larger  pulse-rate 
changes,  there  is  in  most  cases  a  corresponding  change  in  the  metabol- 
ism, a  fall  in  the  pulse-rate  being  accompanied  by  a  downward  tendency 
in  the  metabolism.  The  changes  are,  however,  by  no  means  uniform, 
and  the  reverse  is  not  infrequently  found,  namely,  a  lowering  in  pulse- 
rate  with  a  slight  increase  in  metabolism.  This  lack  of  harmony 
between  pulse-rate  and  metabolism,  w^hich  is  more  particularly  evident 
with  the  girls,  is  sufficient  to  show  that  with  children  in  the  growing 
period  there  apparently  is  much  less  correlation  between  pulse-rate 
and  metabolism  with  the  same  child  than  is  found  either  with  younger 
children  or  with  adults. 

When  the  data  are  examined  with  reference  to  their  grouping  as  to 
sex,  some  difference  is  shown  in  the  values.  It  might  be  expected  that 
the  boys  would  give  results  for  the  second  day  but  little,  if  any,  lower 
than  for  the  first  day,  as  they  would  naturally  be  less  apprehensive 
and  sensitive  to  outside  influences  than  the  girls  and  even  enjoy  the 
novelty  of  the  experience.  The  data,  however,  show  that  with  the 
boys  there  was  almost  invariably  a  fall  on  the  second  day,  but  three 


100  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

cases  out  of  the  thirteen  giving  an  increase.  The  pulse-rate  also 
shows  a  fall  in  all  but  three  cases,  but  no  one  of  these  three  was  simul- 
taneous with  the  rise  in  the  metabolism.  Unfortunately,  the  data  for 
the  girls  are  somewhat  meager  as  compared  with  those  for  the  boys. 
With  four  of  the  six  girls  the  metabolism  rose  on  the  second  day,  but 
with  two  of  the  girls  the  rise  was  insignificant.  The  pulse-rate  almost 
invariably  fell  slightly.  Neither  the  boys  nor  the  girls  show  a  differ- 
ence in  the  comparison  of  results  due  to  age.  The  slight  changes 
noted  between  the  two  sexes  must  be  considered  primarily  of  a  psycho- 
logical and  only  secondarily  of  a  metabolic  nature. 

The  values  in  table  24  thus  demonstrate  that  the  element  of  novelty 
plays  no  appreciable  role  in  the  basal  metabolism.  This  finding  is  in 
full  accord  with  the  recent  series  of  observations  by  Hendry,  Carpenter, 
and  Emmes1  on  a  group  of  medical  students,  and  makes  it  seem  all  the 
more  probable  that  the  small  amount  of  preliminary  training  considered 
absolutely  essential  for  metabolism  measurements  may  be  reduced  to  a 
minimum.  Apparently,  with  complete  muscular  repose,  the  influence 
on  the  pulse-rate  of  previous  experience  in  the  respiration  chamber  is, 
with  children,  of  minor  significance. 

METABOLISM  AS  AFFECTED  BY  GROWTH. 

GENERAL  METHODS  OF  STUDY. 

An  ideal  study  of  the  metabolism  of  children  from  birth  to  puberty 
would  be  the  continuous  measurement  of  the  same  child  at  frequent 
intervals  throughout  this  period  of  life.  All  past  experience  has 
shown  that  the  physiological  activities  of  a  child  can  by  no  means  be 
represented  by  a  straight  line  or  by  a  regular  curve  function,  for  there 
are  gross  irregularities  which  are  inexplicably  and  inherently  a  part 
of  physiological  life.  Accordingly  it  is  necessary  to  base  deductions 
not  upon  the  analysis  of  the  metabolism  of  one  child  alone,  but  upon 
the  metabolism  of  several  children.  Hence  we  felt  it  our  duty  to 
obtain  measurements  for  a  number  of  boys  and  girls  during  as  long  a 
period  of  life  as  they  were  available.  The  children  of  wet-nurses 
could  be  more  or  less  controlled  from  birth,  but  as  each  year  passed 
they  became  more  widely  scattered,  and  consequently  it  was  increas- 
ingly difficult  to  secure  them  for  observation.  But  even  under  these 
conditions  we  were  able  to  hold  and  to  study  a  representative  number 
of  these  children.  In  all,  studies  were  made  with  23  children  over 
varying  periods  of  tune.  In  no  instance,  however,  could  we  approx- 
imate the  ideal  of  intermittent  measurements  from  birth  to  puberty, 
for  after  three  or  four  years  of  observation  it  became  impossible  to 
keep  in  touch  with  the  children. 

1  Hendry,  Carpenter,  and  Emmes,  Boston  Med.  and  Surg.  Journ.,  1919,  181,  pp.  285,  334,  and 


METABOLISM   AS   AFFECTED   BY   GROWTH.  101 

While  such  a  method  of  intermittent  study  may  still  be  considered 
as  the  ideal  method,  since  it  not  only  supplies  an  index  of  the  individual 
variations  for  the  same  child  from  age-period  to  age-period,  but  also 
variations  for  different  children  at  the  same  age  and  weight,  it  became 
necessary  for  us,  in  the  absence  of  "ideal"  conditions,  to  rely  upon  the 
accumulation  of  a  considerable  mass  of  evidence  for  not  only  the  23 
children  who  were  studied  more  or  less  continuously,  but  likewise  a 
large  number  of  isolated  observations  on  other  children.  This  col- 
lection of  more  or  less  isolated  data,  when  combined  with  the  semi- 
continuous  observations,  makes  possible  the  charting  of  a  considerable 
mass  of  material  regarding  the  metabolism  of  children  in  the  period 
from  birth  to  puberty,  thus  supplying  an  excellent  index  of  the  general 
trend  of  the  metabolism  of  a  child. 

By  this  method  of  procedure  it  is  perfectly  legitimate  to  consider 
values  obtained  with  the  same  individual  with  changes  in  age  and 
weight  of  some  magnitude  as  representative  of  a  new  child  at  the  indi- 
cated age  and  weight.  The  basal  metabolism  of  an  adult,  as  measured 
from  month  to  month  and  from  year  to  year  in  the  decade  from  20  to 
30  years  of  age,  does  not  vary  greatly  as  a  result  of  a  change  in  age, 
and  there  is  usually  in  this  time  no  material  change  in  weight  or  height. 
With  children,  on  the  other  hand,  the  rapid  growth  and  changes  in 
stature  and  weight  make  it  wholly  illogical  to  average  the  values 
found  for  any  child  during  a  considerable  range  in  age  and  to  consider 
that  the  result  represents  the  true  average  value  for  that  child.  In 
other  words,  a  child  of  1  year  is  one  individual,  but  a  child  of  1|  years 
is  still  another  individual.  Accordingly,  in  grouping  the  children  for 
general  consideration,  a  definite  method  of  selection  was  followed  in 
determining  the  degree  of  change  in  either  weight  or  age  which  would 
make  it  desirable  to  consider  the  child  as  a  new  individual.  (See 
page  131.) 

In  analyzing  our  experimental  data,  we  naturally  turn  first  to  the 
picture  presented  by  the  results  for  individual  children  with  whom 
observations  were  continued  for  several  months  or  years.  Following 
this  treatment  of  the  data,  we  may  properly  proceed  to  summary 
tables  and  charts  giving  the  results  for  all  of  the  children  studied, 
including  not  only  those  data  representing  long  periods  of  time,  but 
also  the  shorter  isolated  determinations  of  the  basal  metabolism  made 
upon  a  large  number  of  children  of  different  ages  who  were  usually 
observed  on  but  one  or  two  closely  following  days. 

METABOLISM  DURING  GROWTH  AS  SHOWN  BY  THE  INDIVIDUAL  CHILD. 
OBSERVATIONS  WITH  SUBJECT  No.  145. 

Of  the  23  subjects  that  were  studied  over  relatively  long  periods  of 
time,  No.  145  (a  girl)  has  been  selected  for  detailed  treatment  to  indi- 
cate the  method  of  procedure  which  was  followed  with  all  of  the  chil- 


102  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

dren.  The  data  for  this  child  are  given  in  table  25.  For  complete 
record  it  has  been  necessary  to  include  data  for  the  body-weight,  height, 
age,  the  estimated  energy  of  food  taken  prior  to  the  experiment,  the 
length  of  time  elapsing  between  the  taking  of  food  and  the  beginning 
of  the  first  observation,  the  carbon  dioxide  produced  per  hour  in  the 
several  successive  experimental  periods,  the  respiratory  quotient,  the 
average  pulse-rate  for  each  period,  the  relative  activity  as  estimated 
from  the  kymograph  records,  notes  as  to  whether  the  subject  was 
asleep  or  awake,  the  total  heat  production  (computed)  per  24  hours, 
and  likewise  the  heat  produced  per  kilogram  of  body-weight  per  24 
hours  and  per  square  meter  of  body-surface  per  24  hours.  The 
relative  activity  is  expressed  on  an  arbitrary  scale  ranging  from  the 
greatest  degree  of  repose  (I)  to  the  greatest  activity  (VI).  The  body- 
surface  was  determined  by  the  Du  Bois  linear  formula  and  direct 
measurements  made  upon  the  subject  for  practically  every  observation. 
As  has  already  been  pointed  out,  while  ideally  the  observations  should 
have  been  made  without  food  in  the  stomach,  this  is  an  abnormal 
condition  for  young  children.  It  will  be  noted  that  as  the  child  grew 
older  the  length  of  time  between  the  feeding  and  the  beginning  of  the 
first  experimental  period  lengthened,  until  it  was  finally  between  4 
and  5  hours  long. 

As  indicated  in  the  outline  of  the  description  of  the  experimental 
procedure,  the  carbon-dioxide  production  was  directly  measured  for 
each  experimental  period.  These  periods  were  approximately  30 
minutes  in  length.  As  it  was  impracticable  to  determine  the  oxygen 
consumption  in  periods  as  short  as  this,  due  chiefly  to  the  difficulty 
in  obtaining  accurate  measurements  of  the  average  temperature  of 
the  air  inside  the  respiration  chamber,  we  determined  only  the  total 
consumption  of  oxygen  for  the  entire  sojourn  of  the  child  inside  the 
chamber.  Thus  for  four  experimental  periods,  each  of  30  minutes, 
the  oxygen  consumption  would  be  determined  only  for  the  full  2-hour 
period  of  the  experiment,  and  this  total  amount  used  in  the  computa- 
tion of  the  respiratory  quotient. 

In  most  of  the  studies  there  was  a  preliminary  period  in  which 
various  adjustments  were  made  and  in  which  the  oxygen  consumption 
was  not  determined.  During  the  preliminary  periods  the  amount  of 
carbon  dioxide  produced  was  almost  invariably  larger  than  in  later 
periods,  this  being  due  to  the  activity  of  the  child,  who  was  frequently 
awake  at  this  time.  The  carbon-dioxide  production  for  these  periods 
is  likewise  recorded  in  table  25,  but  the  measurements  of  the  oxygen 
consumption,  which  were  used  for  computing  the  respiratory  quotients, 
were  made  only  in  the  main  periods  of  the  observation,  i.  e.,  those 
represented  by  the  values  inclosed  in  brackets.  It  occasionally  hap- 
pened that,  even  during  the  preliminary  period,  the  carbon-dioxide 
production  was  at  a  minimum.  Thus,  on  April  2,  1917,  the  carbon- 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


103 


TABLE  25. — Results  of  observations  on  the  gaseous  exchange  of  No.  145  (girl). 


•S 

H 

Heat  (computed) 

• 

a 

.9  . 

I, 

I 

per  24  hours. 

5 

g 

Date. 

3  1 

11 

jl 

o1 

! 

ii 

f 

1 

Remarks. 

11 

"8  o 

g1! 

1 

3 

| 

a- 

a 

•I 

.s-s 

'3 

,0 

•§   3 

'a 

£ 

3 

*l 

§ 

"1 

5 

a 

P: 

a' 

1 

l 

*I 

" 

a 

1916 

\cals. 

h.  m. 

0m«. 

cals. 

cals. 

cals. 

June  15 

5  mos.  ;  62      80 

1  30 

4.78 

i 

(337 

64  1  1,109 

in 

i 

cm.;  5.27 

4.71 

\  0.84 

1  332 

63  !  1,092 

117 

i 

Probably 

kilos. 

4.94 

I  348 

66  !  1,145 

116 

i 

asleep. 

4.46'  J 

[315 

60  !  1,036 

119 

i 

June  16 

5.22  kilos.       80 

30 

7.9l!    , 

580 

111  1  1,908 

126 

IV 

4.38 

321 

61     1,056 

117 

i 

4.87 

357 

68     1,174 

116 

ii 

4.34 

0.80 

318 

61     1,046 

118 

i 

Do. 

4.64; 

340 

65 

1,118 

117 

ii 

4.93 

361 

69 

1,188 

118 

in 

Nov.  22 

10  mos.; 

160 

1 

8.70  

608 

66     1,310 

117 

n 

Asleep. 

70  cm.; 
9.19  kilos. 

8.86  } 
6.78   1  n  OK 
8.01       °'85 

619 
474 
560 

67 
52 
61 

1,334 
1,022 

1,207 

113 
117 
112 

in 
i 
in 

1  Probably 
J   asleep. 

8.23  J 

575 

63 

1,239 

120 

VI 

Dec.     4 

9.50  kilos. 

130 

30 

7.64  

511 

54 

1,099 

102 

II 

| 

7.94  } 
7'99      090 

(531 
534 

56 
56 

1,142 
1,148 

111 

108 

II 

III 

[Asleep. 

7.55      U<9° 

505 

53 

1,086 

111 

II 

J 

11.23  J 

751 

79 

1,615 

126 

V 

Dec.  22 

11  mos.; 

150 

0 

8.26  

543 

53 

1,042 

110 

I 

Do. 

72.5  cm.; 

7.90 

519 

51 

996 

114 

II 

Do. 

10.2  kilos. 

7.80 
8.90 
7.73 

0.92 

513 

•  585 
508 

51 
58 
50 

985 
1,123 
975 

111 
114 
109 

I 
II 

I 

}  Probably 
J    asleep. 

9.22 

606 

60 

1,163 

113 

V 

1917 

Jan.   11 

lyr.; 

150 

1 

7.08 

477 

46 

928 

103 

I 

Asleep. 

73.5  cm.; 

8.88 

599 

57 

1,165    113 

II 

Probably 

10.5  kilos. 

asleep. 

7.32 

0.89 

494 

47 

961 

106 

II 

Asleep. 

8.49 

573 

55  !  1,115 

113 

II 

Awake, 

then 

asleep. 

Jan.   31 

10.9  kilos. 

2601 

0 

8.80 

.... 

583 

53  I  1,094 

106 

IV 

8.27 

f548 

50  I  1,028 

105 

II 

1 

8.40 

\  0.91 

{  557 

51 

1,045 

111 

I 

[  Asleep. 

8.74 

J 

[579 

53 

1,086    106 

II 

J 

10.14 

672 

62     1.261J  119 

VI 

Feb.  192 

lyr.  Imo.; 

470» 

30 

9.22 

606 

54     1,104    112 

I 

) 

76.0  cm.; 
11.3  kilos. 

8.59 
9.09 

}  0.92 

f564 
\597 

50     1.027J   113 
53  !  1,087    118 

I 
I 

\    Do. 

13.86 

911 

81     1,659    136 

V 

Mar.  15 

1  yr.  2  mos.  ; 

2404 

30 

10.40 

701 

59     1,247    118 

VI 

76.0  cm.; 

7.68 

1  

(518 

44        922    105 

II 

} 

11.8  kilos. 

8.53    1   n  CQ 

575 

49     1,023    110 

II 

\    Do. 

8.73       °'89 

589 

50 

1,048 

104 

II 

J 

10.84J  J 

731 

62 

1,301 

V 

1  Includes  120  cals.  taken  4  hours  before  the  observation. 

2  Rectal  temperature  at  beginning  of  observation  was  99.8°  F.;  at  end,  100.5°  F. 

3  Includes  100  cals.  taken  3j  hours  before  the  observation. 

4  Includes  100  cals.  taken  about  4  hours  before  the  observation. 


104  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


TABLE  25. — Results  of  observations  on  the  gaseous  exchange  of  No.  145  (girl) — Continued. 


5 

W) 

• 

Heat  (computed) 

st 
fj 

•3 

11 

£si 

per  24  hrs. 

i 

2 

i 

T)  3 

5| 

1 

""t 

o1 

^ 

s"§ 

I 

r3 

i 

Date. 

P 

ii 

|| 

1 

3 

1 

H 

P, 

c3 

1 

Remarks. 

ij 

fw 

Jo 

JS 

|| 

i 

£ 

.•g 
M 

|l 

? 

|D 

1 

a 
< 

1 

Q 

(2 

* 

*a 

1917 

cals. 

h.  m. 

gms. 

caZs. 

cals. 

cals. 

Mar.  27 

12.1  kilos. 

3201 

0 

9.00 

.... 

612 

51 

1,048 

103 

ii 

Asleep. 

9.00 

(612!     51 

1,048 

101 

ii 

Do. 

8.95 

I      f|    QQ 

I  610 

50 

1,045 

105 

i 

1  Probably 

8.83 

f     U.OO 

1  601 

50 

1,029 

108 

i 

/   asleep. 

9.46 

J 

[644 

53 

1,103 

108 

in 

Apr.     2* 

12.0  kilos. 

140 

0 

8.73 

589 

49 

1,026 

109 

i 

9.09 

613 

51 

1,068 

112 

ii 

[  Asleep. 

9.55 

0.89 

644 

54 

1,122 

113 

ii 

J 

9.97 

672 

56 

1,171 

121 

IV 

Apr.  20 

1  yr.  3  mos.  ; 

2403 

1 

8.61 

'591 

47 

998 

105 

ii 

\  Probably 

78.0  cm.; 

8.66 

0  87 

594 

47 

1,003 

101 

ii 

/    asleep. 

12.5  kilos. 

8.43 

579     46 

978 

97 

in 

Asleep. 

9.49 

651      52 

1,100 

105 

IV 

May  15 

1  yr.  4  mos.  ; 
78.5  cm.; 

320< 

30 

9.24 
8.10 

}  

618     49 

(541      43 

1,035 
906 

100 
92 

IV 

II 

\  Probably 

12.6  kilos. 

8.65 

[  0.90 

\  578     46 

968 

97 

III 

/   asleep. 

9.58 

J 

[640     51 

1,072 

100 

V 

May  18 

12.5  kilos. 

310* 

0 

10.05 

660     53 

1,065 

106 

V 

9.74 

640     51 

1,032 

100 

IV 

8.25 

0.92 

542      43 

874 

99 

I 

Probably 
asleep. 

8.61 

566     45 

913 

97 

II 

Asleep. 

10.14 

666     53 

1,074 

108 

VI 

June  20 

1  yr.  5  mos.; 
80  cm.; 

640« 

30 

10.51 
9.30 

I  

709!     53 
f  6271     47 

1,142 
1,010 

108 
103 

III 
I 

\  Probably 

13.4  kilos. 

9.79 

\  0.98 

\  660 

49 

1,063 

110 

I 

/    asleep. 

13.59 

J 

[917 

69 

1,4771  119 

V 

June  21 

13.4  kilos. 

(7) 

(7) 

9.92 

646 

48 

1,040!  102 

IV 

8.67 

565 

42 

910 

98 

II 

} 

9.29 

0.93 

•  605 

45 

974 

105 

I 

[  Asleep. 

9.69 

631 

47 

1,016 

95 

I 

Nov.    6 

15.1  kilos. 

170 

30 

9.93 

653 

43 

978 

84 

I 

Do. 

9.03 

593 

39 

888 

89 

I 

Do. 

9.96 

0.92 

•  654 

43 

979 

91 

I 

Probably 

asleep. 

11.71 

769 

51 

1,151 

100 

V 

Nov.  15 

1  yr.  10 

310» 

1  30 

12.05 

109 

VI 

mos.;  86.5 

9.45 

87 

rv 

Asleep, 

cm.;  15.2 

sobbing. 

kilos. 

1  Includes  100  cals.  taken  about  3^  hours  before  the  observation. 

1  Rectal  temperature  at  beginning  of  observation  waa  100.5°  F. ;  at  end,  99.8°  F.     Bad  diarrhea 

on  two  preceding  days;  cutting  teeth. 

J  Includes  100  cals.  taken  about  4£  hours  before  the  observation. 
4  Includes  100  cals.  taken  4  hours  before  the  observation. 

6  Includes  170  cals.  taken  4  hours  before  the  observation. 
'  Includes  230  cals.  taken  4  hours  before  the  observation. 

7  Energy  of  food  not  known.     Probably  at  least  150  cals.  were  taken  just  before  the  observation. 

8  Includes  140  cals.  taken  about  5^  hours  before  the  observation. 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


105 


TABLE  25. — Results  of  observations  on  the  gaseous  exchange  of  No.  145  (girl) — Continued. 


5 

H 

Heat  (computed) 

1| 

1 

"3  a 
8.2 

«  § 

1 

per  24  hours. 

1 

•5 

^ 

Date. 

1| 

ll 

|| 

H"*3 

b 

| 

|| 

I 

1 

1 

Remarks. 

.S  "3 
so  o 

•r?    r* 

I* 

|-§ 

ll 

.1 

1 

1 

d-1 

| 

1 

.83 

< 

1 

j! 

•°   3 

a-« 

0 

H 

1 

II 

1 

1 

1918 

cals. 

h.  m. 

gms. 

cals. 

cals. 

cals. 

Jan.   18 

2  yrs.; 

170 

5 

12.74 

111 

VI 

90.0  cm.; 

12.48 

93 

IV 

15.4  kilos. 

Jan.    19 

15.3  kilos. 

120 

5 

8.40 

582 

38 

841 

80 

I 

Asleep. 

9.34 

0.86 

647 

42 

935 

85 

I 

Do. 

11.24 

779 

51 

1,126 

103 

III 

Mar.    5 

2  yrs.  2 

90 

5  30 

7.99 

539 

35 

797 

72 

I 

Do. 

mos.;  91.0 

9.20 

0.89 

620 

41 

917 

74 

II 

Do. 

cm.;  15.2 

10.30 

695 

46 

1,028 

85 

III 

Asleep, 

kilos. 

but  waked 

May  16 

2  yrs.  4 

170 

4  30 

8.98 

] 

f628 

40 

946 

69 

I 

] 

mos.;  94.0 

8.55 

I     f\  OK 

1  598 

38 

901 

67 

II 

Asleep. 

cm.;  15.8 

9.88 

f  U.ou 

|  691 

44 

1,041 

70 

I 

J 

kilos. 

13.46 

J 

[941 

60 

1,417 

96 

VI 

May  22 

15.7  kilos. 

200 

4 

13.63 

971 

62 

1,458 

93 

VI 

8.16 

f581 

37 

872 

69          I 

Do. 

8.70 

0.83 

I  620 

40 

931 

71 

I 

Do. 

8.94 

[637 

41 

956 

73 

III 

Probably 

Nov.    5 

16.7  kilos. 

210 

4 

13.22 

969 

58 

1,400 

100 

VI 

eep. 

9.92 

}  

f727 

43 

1,051 

78 

I 

Asleep. 

9.10 

}•  0.80 

\  667 

40 

964 

76 

II 

Do. 

11.60 

j 

[851 

51 

1,230 

78 

III 

Awake, 

then  asleep. 

Nov.  13 

2  yrs.  10 

280 

4 

14.38 

1024 

62 

14,95 

93 

VI 

mos.;  96.5 

9.18 

} 

[654 

40 

955 

76 

I 

Asleep. 

cm.;  16.4 

7.98 

\  0.83 

\  568 

35 

829 

71 

I 

Do. 

kilos. 

10.60 

J 

[755 

46 

1,102 

83 

IV 

1919 

Jan.   16 

3  yrs.; 

200 

3  30 

10.89 

761 

45 

1,119 

93 

V 

97.5cm.; 

9.26 

^ 

647 

38 

952 

75 

I 

Do. 

17.0  kilos. 

12.28 

>  0.85 

858 

51 

1,262 

77 

IV 

Jan.   17 

16.8  kilos. 

220 

4  30 

10.02 

' 

735 

44 

1,081 

71 

I 

Do. 

9.56 

701 

42 

1,031 

76 

III 

Asleep, 

0.80 

but  rest- 
less. 

9.36 

686 

41 

1,009 

73 

I 

Asleep. 

11.74 

861 

51 

1,266 

86 

V 

Mar.  10 

17.5  kilos. 

234 

4 

13.27 

927 

53 

1,324 

94 

VI 

9.86 
9.58 

|  0.85 

/689 
\670 

39 
38 

984 
957 

71 

71 

I 
III 

Do. 

Asleep, 

then  awake. 

Mar.  17 

3  yrs.  2 

254 

4 

9.96 

/716 

41 

1,036 

72 

II 

Asleep. 

mos.;  98.5 

8.94 

' 

\643 

37 

931 

67 

I 

Do. 

cm.;  17.5 

14.50 

1043 

60 

1,509     97 

VI 

kilos. 

June  13 

3  yrs.  5 

319 

4  30 

11.50 

789 

45 

1,126     88 

III 

mos.;  101.5 

9.28 

1 

/637 

36 

909     72 

I 

Do. 

cm.;  17.5 

9.94 

>  0.87 

\682 

39 

973 

72 

I 

Do. 

kilos. 

June  14 

17.4  kilos. 

249 

4 

12.09 

924 

53 

1,300 

88 

V 

10.38 
9.38 

}0.76 

(793 

\717 

46 
41 

1,115      66 
1,008     70 

I 
I 

Do. 
Do. 

106  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

dioxide  production  in  the  preliminary  period  was  8.73  grams,1  while 
the  lowest  during  the  subsequent  periods  was  but  9.09  grams,  even 
when  the  child  was  asleep.  But  this  case  is  exceptional. 

In  the  first  observation  with  No.  145,  that  of  June  15,  1916,  the 
carbon  dioxide  produced  in  the  first  three  periods  varied  only  from 
4.71  to  4.94  grams  per  hour.  This  is  an  astonishingly  good  agreement 
between  periods  and  is  in  large  part  explained  by  the  fact  that  the 
relative  activity  (indicated  on  an  arbitrary  scale)  was  I  in  all  three  of 
the  periods  and  the  child  was  probably  asleep  the  entire  time.  Since 
the  carbon  dioxide  values  agreed  so  well,  as  a  natural  consequence  the 
values  for  the  computed  heat  for  these  three  periods  likewise  agree 
well  with  each  other.  The  carbon-dioxide  production  and  heat  for 
the  fourth  period  were  somewhat  lower  than  for  the  other  periods 
and  thus  represent  the  absolute  minimum  as  determined  for  this  day. 

Before  further  consideration  of  the  data  in  table  25,  the  possible 
errors  entering  into  the  measurements  for  any  given  period  should  be 
pointed  out.  For  example,  the  measurement  of  the  carbon-dioxide 
production  for  the  individual  periods  is  based  upon  the  increase  in 
weight  of  a  set  of  absorbing  bottles  containing  soda-lime  and  sulphuric 
acid.  This  requires  the  weighing  of  the  bottles  at  the  beginning 
and  the  end  of  each  period.  While  all  such  weighings  are  verified 
by  a  second  observer,  an  error  in  either  one  of  these  weights  will 
obviously  affect  the  value  for  the  carbon-dioxide  production  for  that 
period.  Such  a  method  does  not  admit  of  duplicate  determinations  for 
any  period — a  palpable  defect.  While  this  is  true  of  practically  all 
modern  methods  in  which  a  respiration  chamber  is  used,  i.  e.,  either 
the  total  amount  of  carbon  dioxide  is  measured  only  by  one  absorbing 
train  or,  if  duplicate  gas-analyses  are  made  of  samples  taken  from  an 
air-current,  but  one  main  meter  or  spirometer  measures  the  air-current, 
still,  in  considering  the  carbon-dioxide  production  for  any  individual 
period,  such  possibility  of  error  must  be  borne  in  mind. 

On  June  15  the  minimum  heat  production  of  315  calories  per  24 
hours  found  in  the  fourth  period  is  reasonably  well  confirmed  by  the 
second  period  with  332  calories  per  24  hours,  which  is  about  5  per  cent 
higher.  An  average  of  these  two  figures  would  therefore  give  the 
most  probable  basal  value  for  the  child  on  this  day.  Since,  however, 
we  have  an  actually  determined  value  of  315  calories,  it  is  clear  that, 
aside  from  technical  errors,  this  heat  production  must  be  the  basal 
or  minimum  heat  production.  In  general,  it  may  be  said  that  the 
minimum  basal  metabolism  is  that  actually  observed,  barring  tech- 
nical errors.  We  are  then  specially  interested  in  evidence  to  prove 
the  probability  of  a  low  value.  Specifically,  is  315  calories  the  real 
minimum  value,  or  shall  we  tacitly  admit  the  probability  of  technical 

1  In  table  25  it  seems  desirable  for  purposes  of  comparison  to  represent  the   carbon-dioxide 
production  on  the  basis  of  one  hour  rather  than  for  the  actual  time  of  observation. 


METABOLISM   AS   AFFECTED   BY   GROWTH.  107 

errors  and  average  the  two  lowest  periods?  Obviously,  if  315  calories 
had  been  the  result  of  duplicate  simultaneous  determinations,  its 
validity  could  hardly  be  questioned. 

In  an  earlier  communication1  we  emphasized  strongly  the  relation- 
ship observable  between  the  pulse-rate  and  the  total  metabolism.  The 
pulse-rate  for  the  four  periods  in  this  experiment  varied  only  between 
111  and  119.  In  the  earlier  observations  just  referred  to,  special 
stress  was  laid  upon  the  countings  of  the  pulse-rate  to  secure  a  suf- 
ficiently large  number  of  counts  to  use  for  comparison  with  the  metab- 
olism which  was  simultaneously  determined.  In  the  present  studies 
the  records  of  the  pulse-rate  were  necessarily  subordinated  in  many 
instances  to  other  technique.  The  average  of  111  for  the  pulse-rate 
in  the  first  period  does  not,  therefore,  necessarily  represent  the  same 
number  of  counts  as  does  the  average  of  119  for  the  fourth  period. 
Effort  was  made,  however,  to  secure  a  sufficient  number  of  counts  to 
give  a  representative  average.  In  this  observation  the  lowest  carbon- 
dioxide  production  per  hour  (that  of  the  fourth  period)  occurred  when 
the  pulse-rate  was  actually  the  highest.  Judging  from  these  data  alone, 
the  correlation  between  pulse-rate  and  metabolism  is  by  no  means 
positive  and  gives  no  further  evidence  of  the  validity  of  the  value  for 
the  metabolism  in  this  fourth  period. 

A  second  observation  of  6  periods  was  secured  on  the  next  day  (June 
16),  The  high  carbon-dioxide  production  for  the  preliminary  period 
of  50  minutes  (which  is  here  given  as  7.91  grams  per  hour)  is  readily 
accounted  for  by  the  activity  in  this  period  represented  by  the  arbi- 
trary designation  IV.  An  accentuation  of  the  pulse-rate  is  also  found 
in  this  period,  with  a  rate  of  126  beats.  The  agreement  in  the  carbon- 
dioxide  production  for  the  several  periods  of  the  main  experiment  is 
reasonably  close,  the  values  ranging  from  4.34  to  4.93  grams  per  hour. 
The  two  lowest  values,  4.38  and  4.34  grams,  were  coincidental  with 
periods  in  which  the  activity  was  but  I.  For  this  day  it  is  obvious 
that  4.34  grams  of  carbon  dioxide,  or  from  318  to  321  calories,  may 
justifiably  be  considered  as  the  minimum.  This  amply  confirms  the 
single  low  value  of  315  calories  noted  for  the  fourth  period  of  the  day 
before.  While,  therefore,  the  value  for  the  last  period  on  June  15 
gave  a  true  measure  of  the  basal  metabolism  on  this  day,  it  has  far 
greater  weight  from  its  substantiation  by  the  values  found  in  the  two 
periods  on  June  16. 

There  was  an  interval  of  5  months  between  the  observation  of  June 
15  and  the  next  on  November  22,  during  which  there  was  a  consider- 
able increase  in  the  length  and  weight  of  the  child.  The  higher  values 
for  the  carbon  dioxide  are  thus  easily  explained  by  these  increases. 
On  November  22  we  have  but  one  period  with  the  lowest  grade  of 

1  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914,  p.  130. 


108  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

muscular  activity.  In  this  period  the  carbon-dioxide  production  was 
6.78  grams  per  hour,  corresponding  to  a  heat  production  of  474  calories 
per  24  hours  or  52  calories  per  kilogram  of  body-weight.  It  is  unfortu- 
nate that  no  other  period  confirms  this  low  value  and  that  no  test  was 
made  until  December  4,  nearly  2  weeks  later.  On  this  latter  date  no 
values  are  found  so  low  as  the  minimum  for  November  22,  although 
one  period  gives  505  calories  per  24  hours  or  53  calories  per  kilogram 
of  body-weight1  as  compared  with  52  calories  observed  on  November  22. 
It  is  not  unreasonable  to  consider  that  these  two  periods  verify  each 
other. 

In  analyses  of  the  period  values  in  these  experiments,  it  is  evident 
that  verification  by  similar  figures  on  another  day  or  duplicate  periods 
on  the  same  day  are  highly  desirable  for  establishing  the  true  minimum 
metabolism.  But  this  is  by  no  means  possible  in  every  day's  experi- 
mentation. Uncontrollable  activities  of  III  or  more  immediately 
rule  out  estimates  for  minimum  values. 

Frankly,  the  pulse-rate  does  not  give  invariably  so  close  a  correla- 
tion with  the  activity  and  the  metabolism  as  we  had  expected.  Thus, 
with  the  low  period  on  November  22,  the  pulse-rate  was  117,  while 
hi  the  most  active  period  it  was  but  120.  The  respiratory  quotients 
in  the  first  four  observations  with  this  child  range  from  0.80  to  0.90 
and  are  fully  in  line  with  the  quotients  which  might  be  expected  from 
the  character  of  the  diet.  No  abnormalities  in  the  respiratory  quo- 
tients are  to  be  seen  in  the  entire  series,  save  that  the  low  value  of 
0.76  in  the  last  observation  on  June  14,  1919,  is  unusual. 

An  examination  of  the  figures  for  the  carbon-dioxide  production  as 
the  observations  progressed,  giving  due  regard  to  the' variations  in 
activity,  shows  that  the  carbon-dioxide  production  during  periods  of 
niinimum  activity  gradually  increased  as  the  age,  height,  and  weight 
increased.  With  this  child,  at  least,  the  minimum  or  basal  metab- 
olism for  any  given  day  is  usually  marked  sharply. 

The  only  experimental  factor  which  varies  in  this  series  of  observa- 
tions, other  than  that  of  activity,  is  the  food,  as  the  amount  taken, 
the  character  of  the  food,  and  the  time  between  feeding  and  the  first 
observation  differ  more  or  less  on  the  several  days.  Theoretically  the 
stimulus  to  cellular  activity  and  to  the  metabolism  increases  with  the 
increase  in  the  amount  of  food  and  with  the  shortening  of  the  interval 
between  the  taking  of  food  and  the  beginning  of  the  observations. 
Practically,  when  one  attempts  to  correlate  the  amounts  of  food  given, 
its  character,  and  the  length  of  time  prior  to  the  observation,  it  is 
only  with  difficulty  that  clear  evidence  can  be  found  of  the  influence 
of  food  upon  the  basal  metabolism.  At  first  sight  it  would  seem  that 
this  point  is  illustrated  by  the  data  for  January  31,  1917,  and  those 

1  When  the  body-weight  changes  without  material  change  in  age,  comparisons  are  best  made  on 
the  basis  of  equal  units  of  weight. 


METABOLISM   AS   AFFECTED   BY   GROWTH.  109 

three  weeks  later  (February  19).  In  one  instance  food  containing  260 
calories  was  taken  immediately  before  the  observations  began;  in  the 
other,  food  containing  470  calories  was  given  30  minutes  before  the 
observations.  The  carbon-dioxide  production  and  total  heat  pro- 
duction on  February  19  are  noticeably  greater  than  those  for  January 
31,  but  owing  to  a  coincidental  increase  in  body-weight,  the  heat 
production  per  kilogram  of  body-weight  and  that  per  square  meter 
of  body-surface  are  practically  unaltered. 

The  pulse-rate  for  February  19  is  distinctly  higher  on  the  average 
than  on  January  31,  although  in  both  observations  the  subject  is 
reported  as  being  asleep,  with,  if  anything,  the  lesser  activity  on  the 
second  day.  A  complicating  circumstance  here  is  the  fact  that  on 
February  19  there  was  a  slight  rise  in  rectal  temperature,  the  record 
at  the  beginning  of  the  observations  being  99.8°  F.  and  that  at  the 
end  100.5°  F.  The  possible  influence  of  food  and  the  possible  influence 
of  a  slightly  febrile  state  are  thus  commingled  and  no  sharp  deductions 
can  be  made. 

The  influence  of  a  slightly  febrile  temperature  seems  to  be  more 
marked  upon  the  pulse-rate  than  upon  the  metabolism  itself.  On  the 
two  days  when  slightly  febrile  temperatures  were  noted,  namely,  on 
February  19,  and  April  2,  1917,  the  pulse-rates  were  noticeably  higher 
than  on  the  days  immediately  before  or  after.  A  corresponding 
increase  in  the  metabolism  is  not  always  definitely  noted.  Still,  the 
very  fact  that  the  pulse-rate  was  so  obviously  disturbed  by  this  slight 
rise  in  temperature  makes  it  all  the  more  important  to  avoid  the  use 
of  observations  when  the  body  temperature  is  even  slightly  febrile, 
especially  in  comparison  experiments. 

Perhaps  one  of  the  most  pronounced  instances  of  the  influence  of 
food  is  that  shown  by  comparing  the  tests  of  May  18  and  June  20, 
1917.  In  the  second  observation  it  would  appear  as  if  the  influence 
of  food  was  clearly  present,  although  the  minimum  value  of  47  calories 
per  kilogram  of  body-weight  is  but  10  per  cent  above  the  mmimum  of 
May  18.  After  the  age  of  2  years,  the  food  was  almost  invariably 
taken  4  to  5  hours  prior  to  the  observations  and  hence  may  be  con- 
sidered as  of  comparatively  little  effect.  After  that  age,  the  calories 
in  the  food  represent  not  far  from  one-third  to  one-fifth  of  the  daily 
requirement.  Experience  with  adults  would  imply  that  at  the  end 
of  4  hours  the  peak  of  the  stimulating  effect  of  food  would  have  been 
considerably  passed.  In  none  of  these  observations,  therefore, 
have  we  the  ideal  condition  of  the  post-absorptive  state.  The  fact 
that  in  most  cases  the  observations  were  made  with  the  child  asleep, 
and  that  in  many  instances,  especially  in  the  later  years,  the  food  had 
been  given  4  or  5  hours  before,  undoubtedly  minimizes  and  compen- 
sates the  influence  of  the  ingestion  of  food.  Still,  in  any  comparison 
of  the  metabolism  of  children  at  varying  ages,  it  must  constantly  be 


110  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

borne  in  mind  that  food  is  almost  always  taken  just  prior  to  a  test 
with  children  under  2  years  of  age  and  that  4  or  5  hours  may  elapse 
between  the  taking  of  food  and  the  beginning  of  the  metabolism  meas- 
urements for  the  older  children. 

On  examining  the  estimates  for  relative  activity  in  the  last  column 
of  table  25,  one  finds  that  the  observations  rarely  show  days  when  no 
periods  with  an  activity  of  either  I  or  II  are  available.  In  only  two 
instances  (November  15,  1917,  and  January  18,  1918)  does  the  factor 
of  persistent  restlessness  appear.  The  data  for  these  two  days  are 
included  in  the  table,  however,  to  give  a  complete  record  of  the  obser- 
vations with  this  child.  Furthermore,  the  values  for  the  carbon- 
dioxide  production  and  the  pulse-rate  for  these  active  periods  are  not 
without  interest. 

Almost  invariably  the  high  activities  (IV,  and  particularly  V  and  VI) 
are  accompanied  by  a  very  great  increase  in  the  metabolism  and  like- 
wise an  increase  in  the  pulse-rate.  The  periods  with  activities  V 
and  VI  usually  correspond  to  the  maximum  heat  production.  But 
absolute  reliance  must  not  be  placed  upon  these  estimates  of  activity 
from  the  kymograph  records,  for  not  infrequently  anomalous  figures 
appear.  Thus,  on  November  22,  1916,  the  last  period  has  an  activity 
of  VI,  with  a  total  metabolism  of  575  calories,  which  is  exceeded  by 
the  first  two  periods  of  the  day,  and  yet  activities  II  and  III  are  re- 
corded for  these  periods.  As  a  rule,  however,  the  metabolism  is 
approximately  proportional  to  the  activity,  and  this  factor  is  a  valu- 
able index  of  the  metabolism  of  a  subject.  The  pulse-rate  is  a  like 
valuable  index,  but  taken  by  itself  it  is  at  times,  especially  with  youth, 
very  unreliable.  The  carbon-dioxide  production,  the  pulse-rate,  and 
relative  activity  taken  together  make  the  selection  of  minimum 
periods  rarely  a  matter  of  great  difficulty.  When  these  are  confirmed 
by  sustaining  figures  on  days  immediately  preceding  or  following,  the 
base-line  becomes  even  more  definitely  fixed. 

Occasionally  low  and  seemingly  aberrant  figures  appear  in  table  25. 
Thus,  in  the  first  experimental  period  on  March  15,  1917,  but  7.68 
grams  of  carbon  dioxide  were  measured,  an  amount  corresponding  to 
but  44  calories  per  kilogram  of  body-weight.  This  value  is  con- 
siderably lower  than  those  found  for  the  next  three  or  four  days  of 
observation;  yet  on  April  20,  1917,  a  heat  production  of  46  calories 
per  kilogram  is  noted,  and  it  is  probable  that  7.68  grams  of  carbon 
dioxide  or  44  calories  per  kilogram  of  body-weight  represents  the 
true  minimum  value  for  March  15. 

While  the  observations  with  the  child  No.  145  were,  with  one 
exception,  larger  in  number  than  those  with  any  of  the  other  children, 
they  are  given  here  in  detail  primarily  to  indicate  the  method  of  study 
and  analysis  of  the  results.  Since  we  are  dealing  with  an  organism 
that  is  continually  increasing  in  age,  length,  and  weight,  a  comparison 


METABOLISM   AS   AFFECTED   BY   GROWTH.  Ill 

of  the  metabolism  values  from  day  to  day  is  best  made  by  some 
graphic  form  of  representation,  such  as  a  chart.  This  comparison  has 
been  made  in  figure  15,  in  which,  to  avoid  confusion  from  a  multi- 
plicity of  points,  the  most  important  (19  in  all)  have  been  selected 
for  plotting. 

In  selecting  the  points  for  a  chart  to  show  the  changes  hi  the  metab- 
olism of  an  individual  as  the  age  increases,  values  for  single  days 
could  not  advantageously  be  used.  They  were  accordingly  not 
infrequently  averaged,  most  of  the  points  in  this  chart  being  made 
up  of  one  or  more  days.  Since  a  selection  of  data  was  necessary,  which 
is  always  undesirable  in  the  preparation  of  scientific  reports,  we  have 
given  in  table  26  a  summary  of  the  actual  minimum  values  and  averages 
used  in  figure  15,  to  show  exactly  how  these  points  were  derived. 
Many  of  these  values  were  likewise  used  on  the  general  charts  or 
group  summaries  (see  figures  23  to  47,  pages  135  to  175),  those  not  so 
used  being  indicated  by  an  asterisk.  Thus,  this  child  (No.  145) 
appears  on  the  general  charts  nine  times,  or  as  nine  different  indi- 
viduals, since  at  all  of  these  nine  points  there  was  sufficient  differ- 
ence in  either  age  or  weight  to  meet  our  requirements  for  the  designation 
of  children  as  new  individuals.  We  believe  such  points  may  properly 
be  included  in  any  general  chart  in  which  values  for  a  number  of 
children  are  represented. 

For  all  of  the  individual  charts  (see  figures  15  to  21,  pages  114  to 
130),  which  were  prepared  primarily  to  indicate  the  basal  metabolism 
at  different  ages  of  the  same  child,  well-substantiated  figures  were 
invariably  sought.  In  some  instances  it  may  be  a  little  difficult  for 
the  reader  to  see  why  certain  values  are  not  selected  or  included  in  an 
average.  For  instance,  the  values  obtained  with  the  child  No.  145 
on  June  21,  1917,  appear  in  figure  15,  while  those  for  June  20,  1917 
(see  table  25),  do  not,  although  one  might  naturally  expect  that  an 
average  for  these  two  days  would  be  used.  Since,  as  poined  out  on 
page  106,  the  possibility  of  an  analytical  error  is  always  present,  it 
can  be  seen  that  the  value  of  565  calories  for  the  first  period  on  June 
21  is  not  substantiated,  except  that  it  agrees  essentially  with  the  low 
values  on  May  18.  The  minimum  value  on  June  20  (627  calories)  is 
noticeably  higher  than  that  found  in  two  periods  on  June  21.  Conse- 
quently, it  was  necessary  here  to  make  a  selection  of  material,  and  it 
seemed  logical  to  choose  for  charting  an  average  of  the  three  periods 
on  June  21,  i.  e.,  600  calories,  rather  than  to  use  the  unsupported 
minimum. 

On  March  5,  1918,  a  very  low  value  of  539  calories  is  noted  in  the 
first  period,  with  620  calories  in  the  following  period.  Here  again  we 
have  an  unsupported  minimum  figure  which  it  seems  unwise  to  include, 
as  there  was  a  change  in  age  of  only  4  months,  i.  e.,  January  to  March. 
The  value  of  620  calories,  although  fitting  well  into  the  general  curve, 


112  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


TABLE  26. — Minimum  heat  production  of  No.  145  (girl).1 


Date 
of 
experiment. 

Age. 

Body- 
weight 
(with- 
out 
cloth- 
ing). 

Height. 

Body- 
surface 
(Du  Bois 
linear 
for- 
mula) . 

Aver- 
age 
pulse- 
rate. 

Heat  (computed) 
per  24  hours. 

Total. 

Per 
kilo. 

Per 
sq.  m. 

1916. 

kilos. 
5.27 
5.22 

cm. 

sq.  m. 

119 
118 

cals. 
315 
318 

cals. 
60 
61 

cals. 
1,036 
1,046 

June  16.  ... 
Average.  . 
Nov.  22  
Dec.    4  
Dec.  22  
1917. 
Jan.   11  
Jan.   31  
Feb.  19  
Mar.  15  
Mar.  27.... 
Apr    20 

5  mos  
10  mos.  1  wk  
*10j  mos. 

5.25 

62.0 

0.304 

119 

317 

61 

1,041 

9.19 
9.50 
10.2 

10.5 
10.9 
11.3 
11.8 
12.1 

70.0 
70.9 
72.5 

73.9 
73.2 
76.1 
76.0 

75.8 

.464 
.465 
.521 

.514 
.533 
.549 
.562 
.584 

117 
111 
109 

103 
105 
113 
105 

108 

474 
505 
508 

477 
548 
564 
518 
601 

52 
53 
50 

46 
50 
50 
44 
50 

1,022 
1,086 
975 

928 

1,028 
1,027 
922 
1,029 

*llmos.  3£  wks  
*1  yr.  5  mo  

1  yr.  2  mos  
*1  yr.  2  mos.  1|  wks. 

105 
101 
97 

591 
594 
579 

47 
47 
46 

998 
1,003 
978 

Average.  . 
May  15.  .  . 

*1  yr.  3  mos  

12.5 

77.9 

.592 

101 

588 

47 

993 

12.6 

.597 
.620 

92 
99 

541 
542 

43 
43 

906 

874 

May  18.  .  .  . 

12.5 

Average.  . 
June  21  

Average.  . 
Nov.    6  

Average.  . 
1918. 
Jan.   19  

*1  yr.  4  mos  

12.6 

79.0 

.609 

96 

542 

43 

890 

98 
105 
95 

565 
605 
631 

42 
45 
47 

910 
974 
1,016 

1  yr.  5  mos  

13.4 

80.0 

.621 

99 

600 

45 

967 

84 
89 
91 

653 
593 
654 
633 

43 
39 
43 

978 
888 
979 

1  yr.  9  mos.  3  wks.  . 
*2yre  

15.1 

86.5 

.668 

88 

42 

948 

15.3 

90.0 

.692 

80 

582 

38 

841 

May  16 
May  22.  .  .  . 

15.8 
15.7 

.664 
.666 

67 
69 

598 
581 
590 

38 
37 

901 

872 

Average.  . 
Nov.    5  
Nov.  13  

2  yrs.  4  mos  

15.8 

94.0 

.665 

68 

38 

887 

16.7 
16.4 

.692 
.685 

76 
71 

667 
568 

40 
35 

964 
829 

Average.  . 
1919. 
Jan.   16  

2  yrs.  10  mos  

16.6 

96.5 

.689 

74 

618 

38 

897 

.680 
.680 

75 
73 

647 
686 

38 
41 

952 
1,009 

Jan.   17  

Average.  . 
Mar.  10  
Mar.  17  

*3  yrs  

16.9 

97.4 

.680 

74 

667 

40 

981 

17.5 
17.5 

.700 
.691 
.696 

71 
67 

670 
643 

38 
37 

957 
931 

Average.  . 
June  13  .... 

3  yrs.  2  mos  

17.5 

98.5 

69 

657 

38 

944 

72 
72 

637 
682 

36 
39 

909 
973 

Average.  . 

*3  yrs.  5  mos  

17.5 

101.3 

.701 

72 

660 

38 

941 

1  Normal,  breast-fed;  adenoids  removed  at  1  yr.;  developed  to  very  large  normal  child. 

NOTE.— The  data  indicated  by  asterisks  (*)  were  not  used  on  the  general  metabolism  charts 
(figs.  23  to  47,  pages  135  to  175)  or  on  the  anthropometric  charts  (figs.  5,  6,  8,  12,  13,  and  14, 
pages  43  to  68)  but  were  used,  along  with  the  other  data  in  this  table,  on  the  individual  chart 
for  this  child  (fig.  15,  p.  114). 


METABOLISM   AS   AFFECTED   BY   GROWTH.  113 

is  likewise  not  supported,  although  this  is  probably  the  true  value  for 
the  basal  metabolism. 

These  selections  seemed  desirable  in  preparing  the  individual  chart 
for  No.  145,  and  it  is  for  the  purpose  of  showing  investigators  the  basis 
for  these  and  similar  selections  that  the  detailed  figures  for  this  child 
are  given  in  table  25.  If  there  is  disagreement  with  our  selection  of 
the  values  shown  in  table  26  and  used  in  the  chart,  other  data  can  be 
chosen,  but  according  to  our  experience,  the  selected  figures  are  the 
most  probable  and  best  experimentally  substantiated  values  for  the 
basal  metabolism  of  this  child  at  the  various  age-levels. 

In  the  analysis  of  the  figures  in  table  25,  little  attention  can  profit- 
ably be  paid  to  the  values  of  heat  per  kilogram  of  body-weight  and  per 
square  meter  of  body-surface,  other  than  to  note  that,  in  general, 
there  is  a  disposition  for  the  heat  per  kilogram  of  body-weight  to 
decrease  as  the  child  grows  older.  An  examination  of  the  values  for 
heat  per  square  meter  of  body-surface  shows  very  considerable  vari- 
ations. Those  variations  ascribable  to  activity  (for  which  note  indices 
in  the  last  column  of  the  table)  should  be  completely  disregarded  in 
any  careful  analysis.  Consequently,  the  detailed  data  do  not  lend 
themselves  to  a  comparison  of  values  from  day  to  day,  from  month 
to  month,  or  from  year  to  year.  It  may  be  noted  roughly  that  with 
high  activity  there  is  almost  invariably  a  high  heat  production  per 
square  meter  of  body-surface,  but  since  we  are  interested  primarily 
in  the  basal  metabolism  of  children,  i.  e.,  the  metabolism  measured 
when  activity  is  not  present,  those  periods  with  high  activity  can  have 
value  only  as  indicating  the  possible  maxima  when  the  child  is  ex- 
tremely restless.  The  distribution  and  range  of  the  basal  values  can 
much  better  be  studied  by  means  of  the  chart. 

The  chart  in  figure  15  indicates  the  changes  in  body-weight,  pulse- 
rate,  total  calories  per  24  hours,  calories  per  kilogram  of  body-weight, 
and  calories  per  square  meter  of  body-surface,  from  the  age  of  5  months 
to  41  months.  Considering  first  the  body-weight,  since  this,  like  the 
other  children  studied,  was  a  normal  child,  we  find  the  curve  quite  in 
line  with  that  normally  expected,  namely,  a  definite  progressive  increase 
throughout  the  entire  period,  the  most  rapid  period  of  change  being 
from  the  fifth  to  the  twenty-first  month.  The  total  calories,  al- 
though showing  considerable  differences  from  tune  to  tune,  range 
from  317  to  667  calories;  in  general  the  curve  is  reasonably  parallel 
to  the  curve  for  body-weight.  In  other  words,  as  the  child  regularly 
increased  in  weight,  height,  and  age,  the  total  calories  per  24  hours 
likewise  regularly  increased. 

With  so  rapidly  changing  an  organism  as  a  growing  child,  compari- 
sons should  be  made  at  two  ages  or  weights  on  some  basis  other  than 
total  calories.  The  two  bases  most  commonly  used  by  physiologists 
have  been  those  corresponding  to  a  unit  of  weight,  i.  e.,  the  calories 


114     METABOLISM   AND   GROWTH   FROM   BIRTH   TO    PUBERTY. 

per  kilogram  of  body-weight,  and  to  a  unit  of  surface,  i.  e.,  the  calories 
per  square  meter  of  body-surface.  These  have  both  been  charted, 
the  former  showing  a  distinct  tendency  for  a  downward  trend  from 
61  calories  at  5  months  to  an  approximate  level  at  38  calories  between 
the  twenty-fourth  and  forty-first  months.  It  thus  appears  that  per 
kilogram  of  body-weight  the  heat  production  of  the  infant  is  consid- 
erably greater  than  that  of  a  child  from  2  to  3  years  of  age. 


No.145(Fj 


18       21      24      27      30     33      36      39     42 

FIG.  15. — Body-weight,  pulse-rate,  and  basal  heat  production  per  24  hours  (No.  145). 

When  the  calories  per  square  meter  are  charted  (and  it  must  be 
recalled  that  we  have  on  this  chart  only  values  representing  the 
minimum  metabolism  at  the  different  ages)  we  find  variations  ranging 
from  1,086  to  841  calories.  Although  the  curve  is  extremely  irregular, 
there  is  a  tendency  downwards,  with  a  slight  rebound  after  24  months. 
As  this  curve  stands,  it  is  apparently  not  so  regular  as  that  for  the 
calories  per  kilogram  of  body-weight,  and  taken  by  itself  gives  very 
little  evidence  of  a  physiological  law  correlating  the  energy  output  and 
the  body-surface  of  the  child.  It  should,  furthermore,  be  recalled 
that  (in  the  case  of  this  child,  at  least)  the  body-surface  was  not 


METABOLISM   AS   AFFECTED   BY   GROWTH.  115 

computed  by  the  erroneous  formula  of  Meeh,  nor  was  it  even  com- 
puted up  to  10  kg.  by  the  more  exact  formula  of  Lissauer,  but  it 
was  actually  determined  from  an  elaborate  series  of  Du  Bois  body- 
surface  measurements.  Even  with  these  most  favorable  conditions 
for  comparing  the  surface  of  the  body  with  the  heat  production,  we 
find  very  great  irregularity  instead  of  the  constancy  hopefully  pre- 
dicted by  earlier  writers. 

The  individual  blocks  indicating  the  height  of  the  pulse-rate  show  a 
tendency  for  this  factor  to  decrease  with  increasing  age,  a  low  level 
being  reached  at  not  far  from  27  months,  with  but  slight  fluctuations 
thereafter. 

Were  the  observations  of  this  series  the  only  ones  available  for 
drawing  final  conclusions,  the  evidence  accumulated  in  tables  25 
and  26  and  in  figure  15  would  warrant  more  refined  analysis,  with  a 
more  extensive  series  of  deductions.  The  hint  of  great  individual 
irregularities  shown  in  all  the  curves  except  that  of  body-weight,  and 
particularly  the  curve  for  calories  per  square  meter  of  body-surface, 
would  alone  make  us  somewhat  cautious  in  drawing  general  con- 
clusions. Since  22  other  subjects  were  studied  (though  not  so  ex- 
tensively, as  a  rule,  as  in  this  particular  case),  it  seems  desirable  first 
to  consider  giving  the  data  individually  by  means  of  charts.  These 
charts  include  children  at  ages  ranging  from  below  5  months  to  more 
than  41  months,  and  of  both  sexes.  Generalized  conclusions  may  then 
be  drawn  from  the  whole  series  in  addition  to  those  tentatively  drawn 
from  the  picture  presented  by  the  data  for  No.  145. 

OBSERVATIONS  WITH  22  CHILDREN  DURING  PERIODS  OF  4  MONTHS  TO  3£  YEARS. 

As  the  detailed  results  for  the  other  22  subjects  studied  over  rela- 
tively long  periods  would  require  considerable  space  for  tabular 
presentation,  it  did  not  seem  desirable  to  give  the  data  in  full,  and  the 
basal  metabolism  of  these  children  is  therefore  shown  by  means  of 
the  curves  in  figures  16  to  21.  Tables  27  and  28  give  the  data  used  in 
the  charts  for  boys  and  girls,  respectively.  These  tables  were  pre- 
pared primarily  to  show  the  data  used  in  plotting  the  general  group 
charts  (figures  22  to  47,  pages  133  to  175),  but  additional  data  em- 
ployed in  plotting  the  individual  charts  (figures  16  to  21)  were  like- 
wise included.  As  in  table  26,  the  data  not  used  in  the  general  charts 
are  indicated  by  an  asterisk,  but  all  of  the  data  in  these  tables  appear 
in  the  charts  in  figures  16  to  21  for  the  individual  children. 

Two  of  these  twenty-two  children,  Nos.  139  and  171,  were  studied 
during  a  period  of  time  as  long  as  that  represented  by  the  chart  for 
No.  145,  i.  e.,  approximately  3  years.  The  others  were  studied  for 
the  most  part  during  periods  of  a  few  months  or  a  year  or  two.  Since 
the  charts  for  Nos.  139  and  171  are  strictly  comparable  with  that  for 
No.  145,  at  least  so  far  as  period  of  study  and  elaborateness  of  measure- 


116  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


TABLE  27. — Minimum  heat  production  of  boys  at  different  ages, 

[Children  normal  unless  otherwise  stated.  The  data  indicated  by  asterisks  (*)  were  not 
used  on  the  general  metabolism  charts  for  boys  (figs.  22  to  45,  pages  133  to  174)  or  on  the  anthropo- 
metric  charts  (figs.  3,  4,  7,  9, 10,  and  11,  pages  40  to  66),  but  were  used,  along  with  the  other 
data  in  this  table  on  the  individual  charts  for  these  children  (figs.  15  to  21,  pages  114  to  130).] 


Subject 
No. 

Age. 

Body- 
weight 
(with- 
out 
cloth- 
ing). 

Height. 

Body- 
surface 
(Du 
Bois 
linear 
for- 
mula). 

Aver- 
age 
pulse- 
rate. 

Heat  (computed) 
per  24  hours. 

Total. 

Per 
kilo. 

Per 

sq.  m. 

1    6 
(F.R.) 
i  27 
106 
107 
108 
1112 
(M.D.) 
114 
115 

117 
118 

119 

'  61 
U24 
(L.L.) 
*125 

8  days  

kilos. 
4.54 

3.86 
3.83 
3.38 
3.40 
3.99 

3.83 
3.83 
3.91 
4.17 

cm. 
52.0 

53.0 
53.0 
51.0 
50.5 

54.0 
55.0 

sq.  m. 
20.283 

.253 
.252 
.232 
.233 
.260 

*  .252 
.243 

124 

129 
108 
124 
135 

127 

125 
118 
127 
135 
125 
129 
124 
129 
124 
106 
120 
108 
124 
121 
126 
118 
118 
98 
122 
114 
118 
118 
122 
125 
107 
107 
108 
95 
88 
94 
138 
119 

117 

cals. 
191 

198 
163 
163 
202 
196 

214 
186 
200 
215 
229 
255 
296 
368 
350 
315 
389 
227 
232 
339 
268 
253 
378 
362 
369 
428 
438 
463 
506 
684 
653 
650 
664 
641 
687 
717 
233 
269 

285 

cals. 
42 

51 
43 

48 
59 
49 

56 
49 
51 
52 
52 
54 
51 
61 
54 
51 
57 
50 
49 
56 
54 
50 
63 
55 
51 
58 
56 
57 
59 
58 
53 
53 
53 
51 
55 
53 
51 
52 

53 

cals. 
675 

783 
647 
703 
867 
756 

849 
765 
791 
799 
881 
941 
876 
1,061 
992 
921 
1,040 
830 
835 
1,003 
856 
832 
1,142 
1,034 
949 
1,044 
1,082 
,132 
,174 
1,278 
,126 
,085 
,116 
1,080 
1459 
1,149 
818 
878 

891 

83  days 

8f  days  

10  days  

11|  days  
17  days  

1  mo  

1  mo  
*  l£mos  

*  1  mo.  3  wks...      . 

*  2  mos.  .  .  . 

4.38 
4.71 
5.86 
6.01 
6.45 
6.23 
6.83 
4.54 
4.71 
6.08 
4.96 
5.10 
6.00 
6.56 

2|  mos  
4j  mos. 

58.5 
63.0 

.271 
.338 

*  5  mos.  3  wks  

*  6  mos.  2  wks  

65!6 
55.0 

58.5 
65.0 
58.5 

64.5 

.374 
.273 
.278 
.338 
.313 

.331 

7  mos.  3  wks  

1  mo.  3  wks  
if  mos  
4  mos  

1  mo.  if  wks  
*  1  mo.  3  wks  
4  mos  
*  4  mos.  3f  wks  

6  mos  

7.21 
7.44 

67.5 

.389 

*  65  mos  

*  7  mos  

7.82 

*  7f  mos  

8.08 
8.51 
11.8 
12.4 
12.4 
12.6 
12.6 
12.5 
13.6 
4.60 
5.13 

5.39 

7  mos.  3f  wks. 

70.5 
79.5 

.431 
.535 

1  yr.  1  mo.  3f  wks.  .  . 
*  1  yr.  4  mos. 

*  1  yr.  4  mos.  If  wks.  . 
*  1  yr.  6  mos  
*  1  yr.  7  mos.  1  wk.  .  .  . 
1  yr.  8  mos. 

&5.5  ' 
90.5 
56.0 
57.0 

58.5 

.593 
.624 

2  .285 
2  .306 

.320 

2  yrs.  1  mo  
2  mos  
2s  mos.  .  .  . 

2f  mos.  .  .  . 

1  Previously  reported  under  initials  given  by  Benedict  and  Talbot,  Am.  Journ.  Diseases  of 

Children,  1914,  8,  p.  1.  Data  for  boy  designated  by  initials  M.  D.  also  reported  by  Bene- 
dict and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914.  Results  for  Nos.  6,  27,  and  61 
reported  under  the  same  subject  number  by  Benedict  and  Talbot,  Carnegie  Inst.  Wash. 
Pub.  No.  233,  1915. 

2  Lissauer  surface. 

1  Certainly  breast-fed.     Probably  many  others  were,  but  we  are  uncertain. 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


117 


TABLE  27. — Minimum  heat  production  of  boys  at  different  ages — Continued. 


Subject 
No. 

Age. 

Body- 
weight 
(with- 
out 
cloth- 
ing). 

Height. 

Body- 
surface 
(Du 
Bois 
linear 
for- 
mula) . 

Aver- 
age 
pulse- 
rate. 

Heat  (computed) 
per  24  hours. 

Total. 

Per 
kilo. 

Per 
sq.  m. 

1126 

128 
'129 
(E.F.) 
'130 
(A.S.) 
U32 
1133 
136 

»137 

(R.E.) 
«138 

141 
6142 

147 
148 

«149 
'(H.T.) 
'150 
»153 

*  2  mos.  1^  wks  
2  mos.  3  wks  
*  3  mos  

kilos. 
5.79 
5.90 
6.12 
7.49 
8.24 
6.32 
7.07 

6.02 

6.18 
5.81 
6.70 
8.19 
8.93 
9.08 
10.6 
11.2 

cm. 
60.5 

sq.  m. 
0.333 

117 
105 
105 
109 
103 
117 
111 

113 

119 
132 
117 
126 
120 
103 
121 
112 
114 

132 
128 
111 
103 
106 
120 
98 
103 
94 
128 
110 
101 
116 
102 
112 
106 
111 
113 
111 
123 
109 
108 
111 
115 
105 
101 

105 
107 
109 

cols. 
276 
267 
290 
370 
413 
296 
311 

305 

318 
329 
365 
445 
454 
461 
588 
622 
324 

414 
473 
577 
590 
592 
656 
645 
642 
658 
382 
372 
340 
456 
437 
496 
367 
347 
391 
379 
411 
412 
467 
512 
537 
559 
420 

428 
378 
396 

cols. 
48 
45 
47 
49 
50 
47 
44 

51 

52 
57 
55 
54 
51 
51 
55 
55 
64 

52 
55 
60 
59 
57 
60 
57 
57 
56 
58 
41 
37 
43 
41 
45 
57 
53 
59 
57 
59 
56 
53 
56 
56 
50 
45 

59 
52 
50 

cols. 
844 
802 
838 
925 
979 
841 
828 

888 

923 
1,006 
980 
1,042 
1,002 
1,034 
1,155 
1,229 
1,070 

1,007 
1,121 
1,274 
1,161 
1,128 
1,247 
1,166 
1,166 
1,163 
1,058 
793 
702 
874 
825 
902 
987 
916 
1,000 
1,024 
1,087 
1,046 
1,074 
1,145 
1,173 
1,073 
912 

1,108 
976 
966 

6  mos  

66.5 
69.5 
61.5 
62.0 

63.0? 

64.0 
62.5 
67.5 
71.0 
73.5 

76.5 

.400 
.422 
*  .352 
*  .380 

*  .341 

.344 
.327 
.373 
.427 
.453 

.509 
*  .303 
*  .411 

7j  mos  

3  mos  

3  mos  
3  mos  

3^  mos. 

3  mos.  2j  wks  

6  mos  

7  mos  

*  7  mos.  1  wk  
9  mos  
*10|  mos  

4^  mos  

5.04 

7.98 
8.56 
9.54 
10.1 
10.3 
10.9 
11.3 
11.3 
11.8 
6.55 
9.14 
9.21 
10.7 
10.6 
10.9 
6.50 
6.55 
6.66 
6.66 
6.92 
7.39 
8.87 
9  15 

60.0 
68.0 

74^5 
79.0 

so.5 

4§  mos.  . 

*  6  mos. 

10  mos.  3j  wks 

.453 
.508 

.526 

1  yr.  4  mos.  3|  wks.  . 
*  1  yr.  6  mos.  2  wks.  .  . 
1  yr.  7  mos.  3  wks.  .  . 
*  1  yr.  9|  mos  
*  1  yr.  10  mos.  3  wks.  . 
1  yr.  11  mos.  3  wks.. 
5  mos. 

82.0 
62.0 
67.5 

.566 
*  .361 
.470 

5  mos. 

*  6  mos. 

8  mos.  1§  wks  
*  9  mos.  1  wk  
*10J  mos  
5  mos.  1§  wks  
5  mos.  1  wk  
*  5^  mos  
*  6  mos  
*  6  mos.  l£  wks  
7  mos. 

70.0 

63^6 
66.0 

.522 

.373 
.379 

68.0 
72.0 

.394 
.435 

9.71 
11.3 
9.33 

7.23 

7.22 
7.87 

78.0 
82.0 
75.0 

72.0 
67.0 

.458 
.521 
*  .457 

*  .386 
.388 

5|  mos  

6  mos  
6  mos.  1  1  wks  
*  1\  mos  

1  Certainly  breast-fed.     Probably  many  others  were,  but  we  are  uncertain. 
8  Lissauer  surface. 

8  Previously  reported  by  Benedict  and  Talbot  under  initials  given,  Am.  Journ.  Diseases  of  Chil- 
dren, 1914,  8,  p.  1.     Data  for  boys  designated  by  initials  E.  F.,  A.  SM  R.  E.,  and  H.  T. 
also  reported  by  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914. 
*  Slow  to  walk  because  of  weak  musculature;  flesh  flabby. 
"Flesh  slightly  flabby;  breast-fed. 

'Above  average  weight. 

7  Shortly  recovered  from  cervical  adenitis. 

'Adenoids  removed  at  2  yrs.;  backward  mental  development;  breast-fed. 


118     METABOLISM   AND   GROWTH   FROM   BIRTH   TO   PUBERTY. 


TABLE  27. — Minimum  heat  production  of  boys  at  different  ages — Continued. 


Subject 
No. 

Age. 

Body- 
weight 
(with- 
out 
cloth- 
ing)- 

Height. 

Body- 
surface 
(Du 
Bois 
linear 
for- 
mula) . 

Aver- 
age 
pulse- 
rate. 

Heat  (computed) 
per  24  hours. 

Total. 

Per 

kilo. 

Per 
sq.  m. 

153 

(cont.) 

'154 
155 

156 
*157 
(P.W.) 
«158 

U69 
161 

'164 
*(R.L.) 
«168 
*(R.S.) 
"170 
(E.G.) 
175 
176 
«177 
182 
186 
187 

8  mos.  3  wks  

*  9^  mos 

kilos. 
8.44 
8.56 
8.77 
10.2 
10.3 
10.8 
11.2 
12.5 
12  9 

cm. 
68.6 

sq.  m. 
0.435 

106 
107 
124 
99 
105 
105 
106 
98 
103 
91 
94 
126    . 
117 
110 
117 
107 
90 
126 
120 

120 
125 
101 
91 
131 
124 
116 
108 
114 
105 
83 
88 
85 
79 
84 
83 
75 
116 
121 
144 
124 
115 

108 
106 

83 
100 

82 
76 
68 

cals. 
453 
484 
547 
553 
606 
648 
657 
667 
664 
668 
769 
452 
407 
413 
486 
711 
665 
457 
439 

383 
425 
377 
405 
518 
535 
586 
572 
612 
541 
588 
650 
622 
623 
671 
720 
719 
413 
429 
473 
503 
455 

531 
479 

587 
720 
649 
800 
716 
791 

cals. 
54 
57 
62 
54 
59 
60 
59 
54 
51 
49 
56 
57 
62 
62 
64 
56 
50 
63 
62 

51 
57 
51 
54 
61 
61 
61 
60 
62 
55 
59 
55 
51 
49 
53 
55 
56 
59 
64 
58 
50 
59 

53 

51 

47 
58 
45 
52 
37 
38 

cals. 
1,041 
1,078 
1,159 
1,095 
1,139 
,161 
,188 
,152 
,139 
,117 
1,263 
1,041 
1,070 
1,076 
1,180 
1,252 
1,118 
1,092 
1,147 

950 

1,057 
936 
983 
1,154 
1,168 
1,213 
,197 
,195 
,067 
,153 
,201 
,134 
,109 
,192 
,274 
,255 
1,104 
1,086 
1,129 
988 
1,140 

1,115 
1,046 

1,057 
1,245 
1,067 
1,244 
883 
951 

*  lyr.  l|wks  
1  yr.  6  mos  

77.6 

.505 

*  1  yr.  7$  mos  
*  1  yr.  10  mos  
2  yrs  

80.0 
84.0 

.553 
.579 

2  yrs.  5  mos  

*  2  yrs  6^  mos 

2  yrs.  9  mos.  3  wks.  . 
*  3  yrs  2  wks 

13.7 
13  7 

87.0 

.598 

6  J  mos  
7  mos  

7.91 
6.54 
6.69 
7.56 
12.7 
13.3 
7.32 
7.11 

7.48 
7.48 

66.0 
68.0 

.434 
.380 

*  7^  mos  
10  mos  
2  yrs.  6  mos  

71.5 
90.0 
93.5 
65.5 
64.0? 

66.5 

.412 
.568 
.595 
.419 
3  .381 

.403 

2  yrs.  10  moa  
7  mos  

7  mos  

7  mos.   .  . 

*  7£  mos. 

*  8  mos. 

7.41 

*  9  mos. 

7.46 

11  mos.  3  wks  

8.48 
876 

70.5 

.449 

1  yr.  6  mos  

9.55 
9.50 
9.94 
9.99 
10.0 
11.7 
12.1 
12.7 
12.7 
13.1 

77.0 

.483 

.510 
.541 

.562 

*  1  yr.  7  mos  
*  1  yr.  8  mos.  3  wks.  .  . 
*  1  yr.  10  mos.  3  wks.  . 
2  yrs.  1  mo  
2  yrs.  6  mos.  1  wk.  .  . 
*  2  yrs.  8  mos.  1  wk..  . 
2  yrs.  10  mos  
*  2  yrs.  10  mos.  1  wk.  . 
*  3  yrs.  1  mo.    .  .  . 

81.0 
82.0 

8416 

*  3  yrs.  1  mo.  1  wk  
7^  mos  
1\  mos  

12.8 
7.03 
6.70 
8.09 
10.1 
7.58 

9.94 
9.37 

12.6 
12.3 
14.6 
15.5 
19.3 
20.6 

66.5 
67.5 
70.5 
77.5 
71.0 

74.0 
74.0 

82.0 

87.5 
88.5 
94.0 
110.5 
111.0 

.374 
.395 
.419 
.509 
3  .398 

a  .476 
3  .458 

.555 

.578 
.608 
.643 
.811 
.832 

9  mos.  .  . 

1  yr.  2  mos  
8£  mos.   . 

9i  mos.   . 

10  mos.   . 

2  yrs.  5  mos.  1  wk.  .  . 
2  yrs.  5  mos.  1  wk..  . 
2  yrs.  7^  mos. 

4  yrs  

4  yrs.  9  mos.  1  wk.  .  . 
5  yrs.  3  wks. 

1  Certainly  breast-fed.     Probably  many  others  were,  but  we  are  uncertain. 

*  Previously  reported  by  Benedict  and  Talbot  under  initials  given,  Am.  Journ.  Diseases  of  Chil- 
dred,  1914,  8,  p.  1.  Data  for  boys  designated  by  initials  P.  W.,  R.  L.,  and  E.  G.  also 
reported  by  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914. 

3  Lissauer  surface. 

4  At  17  mos.  had  diarrhea;  lost  weight,  then  gained;  had  frequent  colds;  normal  development. 
6  Approximately  normal. 

8  Overnourished. 


METABOLISM   AS  AFFECTED   BY   GROWTH. 


119 


TABLE  27. — Minimum  heat  production  of  boys  at  different  ages — Continued. 


Subject 
No. 

Age. 

Body- 
weight 
(with- 
out 
cloth- 
ing). 

Height. 

Body- 
surface 
(Du 
Bois 
linear 
for- 
mula). 

Aver- 
age 

pulse- 
rate. 

Heat  (computed) 
per  24  hours. 

Total. 

Per 
kilo. 

Per 
sq.  m. 

kilos. 

cm. 

83.  m. 

cals. 

cals. 

cals. 

192 

5  yrs.  6  mos.  3  wks.. 

18.8 

106.0 

0.758 

90 

866 

47 

1,143 

1193 

5  yrs.  7  mos.  3j  wks.  . 

23.7 

118.0 

.903 

70 

855 

36 

947 

194 

5  yrs.  9  mos.  1  wk.  .  . 

19.8 

107.5 

.820 

86 

813 

41 

991 

197 

6  yrs.  9  mos.  3  wks.. 

19.9 

114.0 

.795 

99 

925 

47 

1,163 

U99 

6  yrs.  10|  mos  

20.2 

115.5 

.812 

72 

843 

42 

1,038 

»201 

7  yrs.  3^  wks  

21.1 

122.5 

.865 

83 

864 

41 

999 

7  yrs.  3  mos.  2j  wks.  . 

24.4 

124.0 

.928 

75 

1,021 

42 

1,100 

202 

7  yrs.  2  mos  

25.2 

121.0 

.940 

74 

944 

37 

1,004 

204 

7  yrs.  2  mos  

19.9 

111.5 

.820 

73 

838 

42 

1,022 

2205 

7  yrs.  2  mos.  1  wk.  .  . 

21.3 

117.5 

.887 

78 

899 

42 

1,014 

'209 

7  yrs.  11  mos  

25.1 

125.5 

1.013 

74 

1,057 

42 

1,043 

211 

8  yrs.  1  mo.  1  wk.  .  .  . 

26.8 

129.0 

1.072 

78 

1,033 

39 

964 

212 

8  yrs.  1  mo.  .  .  . 

21.1 

120.5 

.888 

69 

785 

37 

884 

<215 

8  yrs.  2j  mos. 

20.8 

116.5 

.845 

94 

984 

48 

1,165 

217 

8  yrs.  6  mos  

26.7 

123.5 

.971 

80 

1,097 

42 

1,129 

6218 

8  yrs.  7  mos. 

24.7 

128.5 

.956 

65 

932 

38 

975 

9  yrs.  5^  mos  

26.8 

133.5 

.988 

78 

1,054 

39 

1,067 

«222 

9  yrs.  3£  wks  

25.0 

122.5 

.942 

71 

1,038 

42 

1,102 

'223 

9  yrs.  1  mo.  2  wks.  .  . 

25.9 

129.0 

.991 

86 

1,011 

39 

1,020 

2224 

9  yrs.  3  mos.  3?  wks.  . 

25.4 

126.0 

1.027 

77 

959 

38 

934 

^228 

9  yrs.  9  mos.  3  wks.  .  . 

28.5 

126.5 

1.003 

79 

1,209 

43 

1,205 

«229 

9  yrs.  11  mos.  .  . 

30.1 

128.0 

1.054 

76 

1,092 

36 

1,036 

232 

10  yrs.  4  mos  

28.1 

127.0 

1.087 

80 

1,037 

37 

954 

»235 

10  yrs.  7  mos.  1  wk.  .  . 

30.3 

134.0 

1.088 

85 

1,015 

34 

933 

236 

10  yrs.  8  mos.  3|  wks.  . 

31.0 

132.5 

1.084 

76 

1,147 

37 

1,060 

237 

10  yrs.  9  mos  

33.6 

139.5 

1.213 

73 

1,192 

36 

983 

240 

11  yrs.  1  mo.  lj  wks.. 

33.8 

138.5 

1.244 

1,230 

36 

989 

»241 

11  yrs.  1^  mos  

30.6 

136.0 

1.100 

'"77 

1,086 

36 

987 

242 

11  yrs.  2  mos.  lj  wks.  . 

26.8 

126.0 

.985 

80 

1,117 

42 

1,134 

«243 

11  yrs.  3  mos.  1§  wks.. 

37.9 

149.5 

1.256 

69 

1,282 

34 

1,021 

«244 

11  yrs.  4§  mos  

29.5 

132.0 

1.083 

63 

1,039 

36 

960 

"245 

11  yrs.  5j  mos..  

31.7 

135.5 

1.165 

61 

1,213 

38 

1,041 

246 

11  yrs.  6  mos  

36.9 

150.5 

1.245 

67 

1,283 

35 

1,031 

2247 

11  yrs.  8  mos.  1  wk..  . 

30.5 

141.0 

1.155 

68 

1,023 

34 

886 

2249 

11  yrs.  11  mos.  3  wks.  . 

29.9 

135.5 

1.187 

63 

1,087 

37 

915 

«250 

12  yrs.  1  mo.  2?  wks.  . 

41.0 

150.5 

1.370 

61 

1,211 

30 

884 

252 

12  yrs.  3  mos.  2  wks.. 

34.1 

139.0 

1.245 

66 

1,167 

34 

937 

253 

12  yrs.  7  mos.  3  wks.  . 

30.4 

140.0 

1.085 

73 

1,163 

38 

1,072 

254 

12  yrs.  7  mos.  3  wks.. 

39.0 

151.0 

1.333 

66 

1,163 

30 

872 

"255 

12  yrs.  8  mos  

37.9 

153.0 

1.303 

67 

1,096 

29 

841 

Z256 

12  yrs.  8  mos.  2£  wks.  . 

32.8 

137.5 

1.221 

72 

1,246 

38 

1,020 

12258 

13  yrs.  8  mos  

50.8 

159.5 

1.494 

63 

1,481 

29 

991 

"259 

14  yrs.  1  mo  

38.2 

151.5 

1.335 

61 

1,200 

32 

899 

"260 

15  yrs.  1  wk  

39.0 

147.0 

1.300 

72 

1,401 

36 

1,079 

1  Tall,  over-nourished. 

2  Slightly  undernourished. 

3  Tall. 

4  Somewhat  thin. 

5  Tall,  thin. 

6  Overnourished. 

7  Fairly  well  developed  and  nourished ;  slightly 

under  par. 


Below  par  mentally. 
Very  muscular. 

0  Stupid,  overnourished. 

1  Tall,  gawky,  slightly  undernourished. 

2  Overnourished;  tall;  puberty. 

3  Thin,  slightly  undernourished. 
'Puberty  (?). 


120     METABOLISM   AND   GROWTH   FROM   BIRTH   TO   PUBERTY. 


TABLE  28. — Minimum  heat  production  of  girls  at  different  ages. 

[Children  normal  unless  otherwise  stated.  The  data  indicated  by  asterisks  (*)  were  not 
used  on  the  general  metabolism  charts  for  girls  (figs.  23  to  47,  pages  135  to  175)  or  on  the  anthropo- 
metric  charts  (figs.  5,  6,  8,  12,  13,  and  14,  pages  43  to  68)  but  were  used,  along  with  the  other 
data  in  this  table,  on  the  individual  charts  for  these  children  (figs.  15  to  21,  pages  114  to  130).] 


Subject 
No. 

Age. 

Body- 
weight 
(with- 
out 
cloth- 
ing). 

Height. 

Body- 
surface 
(Du 
Bois 
linear 
for- 
mula). 

Aver- 
age 
pulse- 
rate. 

Heat  (computed) 
per  24  hours. 

Total. 

Per 
kilo. 

Per 
sq.  m. 

i  2 
i  12 
i  26 
1  35 

i  48 

»  49 
109 
U10 
«(E.P.) 
Ill 
<113 

«116 

KA.C.) 
<120 
KB.D.) 
122 

123 

«127 

10  days  

kilos. 
3.73 
4.20 
3.56 
4.42 
5.07 
7.17 
4.81 
5.54 
2.68 
3.86 
3.71 

3.57 
3.65 
3.99 
440 

cm. 
53.0 
53.0 
50.0 
54.0 
58.5 
64.5 
56.0 
61.0 
48.5 
51.5 
51.0 

53.0 
53.0 

sq.  m. 
=0.248 
.268 
.239 
.278 
.304 
.384 
.293 
.323 
.199 
.253 
.247 

*  .240 
.249 

96 
133 
110 
117 
134 
125 
127 
139 
116 
114 
122 

147 
141 
135 
129 
134 
119 
133 
-  120 
115 
120 
126 

122 

126 
135 
136 
136 
127 
129 
131 
129 
117 
124 
114 
112 
114 
115 
127 

cats. 
152 
199 
185 
198 
223 
329 
211 
388 
139 
200 
182 

200 
173 
178 
211 
207 
217 
253 
289 
324 
351 
163 

274 

257 
299 
329 
597 
653 
235 
251 
280 
253 
312 
325 
334 
410 
255 
468 

cafe. 
41 
47 
52 
45 
44 
46 
44 
70 
52 
52 
49 

56 
47 
45 
48 
45 
44 
51 
53 
54 
54 
55 

57 

50 
53 
55 
59 
63 
61 
57 
63 
55 
51 
54 
53 
61 
51 
58 

cols. 
611 
743 
774 
712 
734 
857 
720 
1,201 
698 
791 
735 

833 
695 
695 
754 
745 
728 
861 
871 
967 
975 
759 

927 

830 
911 
948 
1,161 
1,251 
963 
923 
1,098 
891 
920 
962 
957 
1,188 
876 
1,125 

9  days  

10  days  

8  days  

1  mo.  1  wk  
4  mos  

1  mo.  1  wk  
2  mos.  3  wks  
11  days  .  .  . 

12^  days.  . 

13  days  .  . 

13  days 

3f  wks. 

*  5  wks. 

*  1|  mos 

1  mo.  3£  wks  
*  2£  mos  

4.55 
4.88 
4.98 
5.54 
6.04 
6.49 
2.99 

4.90 

5.15 
5.62 
6.03 
10.1 
10.4 
3.85 
4.37 
4.44 

57.5 

.278 

4  mos  
*  4  mos.  3?  wks  
5  mos.  3  wks  

63.0 

.332 

66.5 

.360 
*  .214 

*  .297 
.309 

1^  mos  

2  mos  

58.0 
58.5 

2  mos.  1  wk  
*  3  mos..  .  . 

3  mos.  3|  wks  
1  yr.  6  mos  

62.5 

78.5 

53.5 

.347 
.514 

.244 

*  1  yr.  6  mos.  3£  wks.  . 
2  mos.  1  wk  

2j  mos. 

2  mos.  3|  wks  

3  mos.  1  wk  

4.59 

6  mos.  1  wk  
6  mos.  3  wks  
7  mos.  1  wk  
8  mos.  3  wks  
2  mos.  3?  wks  
9^  mos  

6.09 
6.06 
6.34 
6.75 
5.03 
8.11 

63.0 

65.6 
57.5 
67.0 

.339 

.345 
.291 
.416 

1  Previously  reported  under  initials  given  by  Benedict  and  Talbot,  Am.  Journ.  Diseases  of 
Children,  1914,  8,  p.  1.  Data  for  girl  designated  by  initials  A.  C.  also  reported  by  Benedict 
and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914.  Results  for  Nos.  2,  12,  26,  35,  48, 
and  49  reported  under-the  same  subject  number  by  Benedict  and  Talbot,  Carnegie  Inst. 
Wash.  Pub.  No.  233,  1915. 

1  Lissauer  surface. 

*  Data  as  previously  published  incorrect. 

4  Certainly  breast-fed.     Probably  many  others  were,  but  we  are  uncertain. 

6  Slightly  undernourished. 

8  During  second  year  had  colds;  continued  to  develop  normally;  breast-fed. 


METABOLISM   AS  AFFECTED   BY   GROWTH. 


121 


TABLE  28. — Minimum  heat-production  of  girls  at  different  ages — Continued. 


Subject 
No. 

Age. 

Body- 
weight 
(with- 
out 
cloth- 
ing). 

Height. 

Body- 
surface 
(Du 
Bois 
linear 
for- 
mula). 

Aver- 
age 
pulse- 
rate. 

Heat  (computed) 
per  24  hours. 

Total. 

Per 
kilo. 

Per 
sq.  m. 

127 
(cont.) 

•131 

»134  (L. 
R.B.) 
*135 

(M.C.) 
<139 

140 
'144 

6.  6146 

H51 
152 
160 

*11  mos.  If  wks  

kilos. 
7.98 

cm. 

sq.  m. 

Ill 
115 
108 
111 
114 
93 
111 
122 
132 
118 
119 
120 
119 
121 
124 
106 

103 

136 
121 
129 
119 
124 
135 
129 
124 
131 
113 
128 
116 
109 
99 
110 
101 
100 
93 
85 
78 
80 
84 
85 
115 
121 
112 
119 
119 
126 
117 
123 
126 

cols. 
453 
500 
486 
485 
549 
474 
235 
279 
277 
311 
335 
314 
340 
351 
353 
331 

333 

315 
280 
339 
314 
325 
406 
419 
484 
528 
491 
516 
511 
531 
525 
590 
549 
607 
579 
655 
608 
601 
656 
624 
334 
353 
445 
360 
419 
355 
357 
417 
444 

cdU. 
57 
61 
56 
57 
61 
53 
54 
60 
57 
59 
60 
55 
58 
59 
58 
55 

54 

61 
53 
59 
52 
53 
58 
51 
54 
55 
50 
51 
51 
50 
47 
48 
43 
45 
44 
47 
43 
41 
46 
43 
66 
45 
42 
43 
46 
63 
55 
71 
70 

cols. 
1,051 
1,131 
1,063 
1,025 
1,138 
1,019 
933 
1,045 
945 
1,003 
1,074 
928 
1,005 
1,057 
1,057 
973 

967 

1,006 
864 
1,000 
952 
926 
1,060 
997 
1,094 
1,110 
989 
1,024 
987 
986 
948 
1,000 
895 
936 
930 
1,026 
953 
918 
1,019 
937 
1,047 
835 
856 
847 
984 
1,086 
997 
1,219 
1,251 

*  1  yr.  If  wks  
*  1  yr.  1  mo  

8.28 
8.62 

*  1  yr.  2f  mos  

8.56 
9.06 
8.89 
4.34 
4.64 
4.86 
5.27 
5  55 

1  yr.  4  mos  

73.0 

0.482 

3  mos. 

55.5 
68.6 

.252 
.310 

*  3  mos.  1  wk  
*  3  mos.  3  wks  
4  mos   1$  wks. 

*  5  mos 

*  6  mos.  1  wk  

5.76 
5.87 
5.97 
6.08 
5.99 

6.17 

5.19 
5.27 
5.75 

*  6  mos.  3f  wks  

*  7  mos  
7  mos.  2f  wks  
4  moa  

62.6 
64.0 

63.0 
63.0 

.333 
»  .340 

»  .347 
.313 

4  mos  
4f  mos  

*  6  mos. 

5.99 

6  mos.  1  wk  
7  mos  

6.11 
7.00 
8.29 
9  03 

65.0 
67.0 
70.0 

.351 
.383 
.420 

9  mos.  1  wk  
*10f  mos 

1  yr.  2  mos.  3  wks.  .  . 
*  1  yr.  4  mos  
*  1  yr.  5  mos  
*  1  yr.  6f  mos  
1  yr.  8f  mos  
*  1  yr.  lOf  mos  
2  yrs.  2f  mos. 

9.67 
9.81 
10.2 
10.0 
10.8 
11.1 
12.3 
12.8 
13.6 
13.4 
14.0 
14.3 

76.0 
82.6 

.476 
.538 

88.0 
92!5 

.590 
.648 

*  2  yrs.  5  mos  
2  yrs.  6  mos.  3  wks.  . 
*  2  yrs.  8  mos.  If  wks.  . 
3  yrs.  2  mos.  3  wks.  . 

96.0 

.638 

14.7 

*  3  yrs.  7  mos.  3  wks.  . 
3  yrs.  9  mos.  3  wks.. 
4  mos.  3  wks  
5  mos  

14.4 
14.7 
6.02 
7.91 
10.6 
8.30 
9.04 
5.64 
6.52 
5.90 
6  31 

99!6 
60.0 
62.0 
67.5 
68.0 
71.0 
60.0 
65.5 
62.5 

'.666  ' 
.319 
.423 
.520 
.425 
.426 
»  .327 
.360 
.342 

9  mos  

5  mos.  1  wk  

7  mos  
6  mos  

6  mos  
7f  mos  

1  Slight  facial  eczema. 

2  Previously  reported  by  Benedict  and  Talbot,  Am.  Journ.  Diseases  of  Children,  1914,  8,  p.  1. 

Data  for  girls  designated  by  initials  L.  R.  B.,  and  M.  C.  also  reported  by  Benedict  and 
Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  201,  1914. 

3  Lissauer  surface. 

4  At  3  yrs.  had  measles;  no  other  illness  except  colds;  breast-fed. 

*  Certainly  breast-fed.     Probably  many  others  were,  but  we  are  uncertain. 
«  See  table  26,  p.  112,  for  data  for  No.  145. 


122     METABOLISM   AND    GROWTH   FROM   BIRTH   TO   PUBERTY. 


TABLE  28. — Minimum  heat  production  of  girls  at  different  ages — Continued. 


Subject 
No. 

Age. 

Body- 
weight 
(with- 
out 
cloth- 
ing). 

Height 

Body- 
surface 
(Du 
Bois 
linear 
for- 
mula) . 

Aver- 
age 
pulse- 
rate. 

Heat  (computed) 
per  24  hours. 

Total. 

Per 
kilo. 

Per 
sq.  m. 

160 

(cont.) 

162 
163 
165 
*166 

167 
*171 

<172 
'173 

kilos. 
7.05 
7.63 
8.12 
8.11 
8.41 
8.15 
8.00 
7.63 
6.24 
7.92 
7.98 
8.62 
9.21 
9.45 
11.1 
11.4 
11.6 
11.8 

cm. 
65.5 

sq.  TO. 
0.375 

126 
114 
113 
117 
119 
111 
119 
116 
93 
116 
119 
126 
109 
105 
96 
105 
84 
97 
91 
95 

cals. 
492 
522 
522 
537 
530 
505 
413 
375 
338 
505 
482 
557 
559 
570 
597 
625 
603 
621 
655 
692 
710 
741 
686 
686 
522 
502 
557 
545 
606 
613 
612 
664 
643 
638 
735 
649 
666 
657 
718 
713 
568 
608 
686 
677 
697 
647 
712 
600 
573 
552 

cals. 
70 
68 
64 
66 
63 
62 
52 
49 
54 
64 
60 
65 
61 
60 
54 
55 
52 
53 
55 
53 
53 
54 
50 
49 
61 
61 
66 
63 
64 
65 
63 
66 
61 
58 
60 
53 
55 
46 
44 
44 
65 
65 
70 
68 
68 
62 
64 
65 
61 
56 

cals. 
1,312 
1,286 
1,283 
1,313 
1,283 
1,268 
1,002 
938 
914 
1,238 
1,100 
1,255 
1,152 
1,171 
1,120 
1,143 
1,075 
1,093 
1,128 
1,155 
1,239 
1,260 
1,179 
1,138 
1,140 
1,210 
1,289 
1,310 
1,303 
1,330 
1,330 
1,425 
1,302 
1,236 
1,269 
1,106 
1,164 
1,053 
1,054 
1,059 
1,246 
1,277 
1,350 
1,317 
1,377 
1,242 
1,292 
1,300 
1,170 
1,131 

*  1  yr 

1  yr.  3j  wka  

68.5 

.407 

*  1  yr.  1?  mos  

*  1  yr  2§  mos 

8  mos  
8  mos.  1  wk  
8  mos.  3  wks  
9  mos.  1  wk  
*10  mos.  3  wks  
*  lyr.  1^  wks  
1  yr.  2|  mos  
*      yr.  4  mos  
yr.  8  mos.  3^  wks.  . 
*      yr.  10  mos  
*      yr.  11  mos.  3  wks.. 
*  2  yrs.  2  mos  

69.5 
63.0 
63.0 
68.5 

i  .412 
i  .400 
.370 
.408 

74.5 

.485 

80.0 

.533 

2  yrs.  4  mos. 

12.0 
13.2 
13.3 

88.0 
88.5 

.581 
.599 

2  yrs.  9^  mos  
*  2  yrs.  11  mos. 

*  3  yrs.  1^  mos. 

13.7 

88 

79 
126 
123 
140 
129 
141 
124 
110 
123 
107 
114 
109 
102 
99 
93 
85 
89 
116 
121 
122 
123 
116 
111 
116 
126 
113 
119 

*  3  yrs.  2  mos. 

13.7 

14.0 
8.52 
8.18 
8.40 
8.70 
9.43 
9.50 
9.75 
10.1 
10.6 
11.0 
12.2 
12.3 
12.1 
14.2 
16.5 
16.2 
8.80 
9.30 

92.5 
69.0 
73.5 

76.5 

.603 
.458 
.415 

.465 

9  mos.  1  wk  
10  mos  
*10$mos  
*  1  yr.  1  J  mos  
1  yr.  2  mos.  1|  wks.  . 
*  1  yr.  3^  mos  
*  1  yr.  4  mos.  3£  wks.  . 
*  1  yr.  5  mos.  1  wk.  .  .  . 
1  yr.  9|  mos  

85.5 

.494 

*  1  yr.  11  mos  

2  yrs.  3  mos.  1  wk.  .  . 
*  2  yrs.  4  mos.  1  wk.  .  . 
*  2  yrs.  5  mos  
3  yrs.  3  mos.  1  wk.  .  . 
4  yrs.  2  mos.  1  wk.  .  . 
*  4  yrs.  3  mos.  2  wks.  . 
11  J  mos  

89.5 

.579 

100.0 
104.5 

.624 
.681 

74.5 

.456 

*  1  yr.  1^  wks  

1  yr.  1  mo.  l£  wks.  .  . 
*  1  yr.  2  mos.  1  wk.  .  . 

9.84 
10.0 

77.0 

.508 

*  1  yr.  3  mos  

10.2 

*  1  yr.  4  mos  
1  yr.  5  J  mos  

10.4 
11.1 
9.22 
9.46 
9.98 

'  80.0  ' 
72.0 

.551 
.461 

11^  mos  

*  1  yr.  1  mo  
*  1  yr.  2  mos  

1  Lissauer  surface. 

2  At  1  yr.  4  mos.  had  measles;  no  other  illness  except  colds;  breast-fed. 

3  At  1  yr.  1  mo.  had  chicken  pox;  no  other  illness  except  colds;  developed  normally;  breast-fed. 

4  Adenoids  removed  when  1  yr.  old. 
s  During  second  year  had  colds. 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


123 


TABLE  28. — Minimum  heat-production  of  girls  at  different  ages — Continued. 


Subject 
No. 

Age. 

Body- 
weight 
(with- 
out 
cloth- 
ing). 

Height 

Body- 
surface 
(Du 
Bois 
linear 
for- 
mula). 

Aver- 
age 
pulse- 
rate. 

Heat  (computed) 
per  24  hours. 

Total. 

Per 
kilo. 

Per 
sq.  m. 

173 
(cont.) 

174 
178 
'179 
180 
181 
2183 
184 
188 
«189 
190 
"191 
<195 
'196 
198 
2203 
"206 

210 

"214 
219 
3220 
221 
225 
'227 
7230 
8233 
«234 
238 
»239 

"248 
"251 
257 

*  1  yr.  3  mos  
1  yr.  5  mos  
*  1  yr.  6|  mos  
2  yrs.  1  mo.  ... 

kilos. 
9.81 
10.6 
11.0 
11.0 
12.4 
14.5 
15.0 
16.4 
15.7 
16.2 
16.6 
22.7 
15.2 
18.7 
16.4 
19.7 
26.4 
23.1 
19.2 
20.8 
23.9 
26.0 
26.0 
23.7 
22.5 
26.1 
24.0 
24.8 
27.9 
29.8 
28.2 
28.0 
27.4 
39.2 
28.8 
30.9 
37.1 

cm. 
"78.0' 

sq.  m. 
0.522 

109 
109 
97 
102 
88 
76 
92 
88 
77 
92 
110 
79 
81 
85 
91 

73 
74 
74 
71 
86 
79 
65 
81 
97 
76 
79 
82 
77 
68 
74 
90 
76 
72 
75 
78 
74 

cols. 
554 
614 
622 
604 
543 
560 
640 
771 
673 
715 
782 
829 
637 
790 
792 
747 
918 
849 
752 
863 
894 
1,002 
930 
880 
977 
902 
924 
919 
999 
896 
923 
944 
984 
1,500 
1,062 
1,012 
1,318 

cols. 
56 
58 
57 
55 
44 
39 
43 
47 
43 
44 
47 
37 
42 
42 
49 
38 
35 
37 
39 
42 
38 
39 
36 
37 
43 
35 
38 
38 
36 
30 
33 
34 
36 
38 
37 
33 
36 

cols. 
1,140 
1,176 
1,154 
1,112 
894 
856 
926 
1,100 
1,028 
999 
1,075 
951 
922 
1,056 
1,191 
915 
926 
964 
956 
1,031 
961 
1,014 
959 
954 
1,042 
883 
1,020 
983 
944 
844 
894 
902 
909 
1,179 
1,026 
920 
1,079 

79.0 
92.0 
98.5 
93.5 
98.5 
97.5 
103.0 
103.5 
116.0 
103.5 
107.5 
99.5 
118.0 
124.5 
119.0 
113.0 
116.0 
122.5 
123.5 
126.0 
125.0 
122.0 
122.0 
120.5 
125.5 
133.0 
131.0 
133.0 
135.5 
133.5 
147.5 
129.0 
138.5 
140.5 

.543 

.608 
.654 
.691 
.701 
.654 
.716 
.728 
.872 
.691 
.748 
.665 
.816 
.991 
.881 
.787 
.837 
.930 
.988 
.970 
.922 
.938 
1.021 
.906 
.935 
1.058 
1.062 
1.033 
1.047 
1.083 
1.272 
1.035 
1.100 
1.222 

2  yrs.  11  mos. 

3  yrs.  8  mos. 

3  yrs.  10  mos.  3  wks.  . 

4  yrs.  3  mos.  3  wks.. 
4  yrs.  4  mos.  1  wk.  .  . 
5  yrs.  1^  mos  
5  yrs.  3  mos.  1  wk.  .  . 
5  yrs.  3|  mos  
5  yrs.  5|  mos  
6  yrs.  3  wks  

6  yrs.  5?  mos. 

6  yrs.  9  mos.  . 

7  yrs.  1  mo.  2  wks..  . 
7  yrs.  4  mos  

8  yrs.  2  wks  
8  yrs.  5  mos.  3  wks.  . 
8  yrs.  2  mos  
8  yrs.  11  mos.  1  wk.  . 
9  yrs.  y  mo.  .  . 

9  yrs.  3i  wks  
9  yrs.  5  mos.  1  wk.  .  . 
9  yrs.  9  mos  

10  yrs.  3  mos  
10  yrs.  5  mos.  2|  wks.  . 
10  yrs.  5  mos.  3j  wks.  . 
10  yrs.  9  mos.  3£  wks.  . 
11  yrs  

12  yrs.  1  mo  
11  yrs.  10  mos.  3  wks.  . 
12  yrs.  2  mos  
13  yrs.  3  mos.  3  wks.. 

1  Flesh  slightly  flabby. 

2  Overnourished. 

3  Slightly  undernourished. 

4  Well  developed  and  nourished,  with  chronic  endocarditis. 
6  Tall,  thin. 

6  Weak  ankles,  the  result  of  old  infantile  paralysis. 

7  Thin. 

8  Overnourished;  puberty. 

9  Puberty  established  at  12  yrs.  1  mo. 

10  Fat,  healthy,  rosy-cheeked. 

11  Puberty  beginning. 

ments  are  concerned,  it  is  of  interest  to  consider  them  somewhat  in 
detail.  It  is  important  to  note  that  the  scale  upon  which  the  charts 
for  these  children  are  drawn  is  somewhat  different  from  that  used 
for  No.  145.  (Compare  figs.  15  and  16.) 


124  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

The  individual  points  in  these  charts  are  so  numerous  as  to  produce 
curves  that  are  by  no  means  smoothed.  The  general  trend  of  the 
body-weight  curves  of  both  Nos.  139  and  171  is  that  of  a  progressive 
increase,  as  is  common  with  a  normal  infant.  The  total  calories  per 
24  hours  fully  substantiate  the  general  line  noted  for  No.  145,  namely, 
a  rather  rapid  rise  until  about  2  years  of  age,  after  which  there  is  a 
tendency  for  a  clearly  defined  rise,  although  at  a  somewhat  slower  rate. 


No.171(F.) 


No.139(F.)r 


FIG.  16. — Body-weight,  pulse-rate,  and  basal  heat  production  per  24  hours 
(Nos.  171  and  139). 

While  emphasis  must  again  be  laid  upon  the  inherent  errors  in  the 
measurement  of  individual  periods,  an  attempt  has  been  made  to 
select  only  such  points  as  were  fully  substantiated  by  the  results  for 
another  period  on  the  same  day  or  on  the  day  immediately  preceding 
or  following.  Consequently  in  these  charts  the  individual  points  can 
for  the  most  part  be  considered  as  truly  representative  of  the  metabolic 
plane  at  the  time  of  measurement.  A  high  point  in  the  total  calories 
is  never  based  upon  a  single  experimental  period.  This  is  emphasized 
to  bring  out  the  fact  that  with  children  the  regularity  in  the  heat 
production  from  day  to  day  is  not  perfect  on  any  basis,  and  rather 
considerable  fluctuations  may  normally  be  expected  to  obtain,  even 
in  periods  with  complete  muscular  repose  and  (though  not  with  a 
true  post-absorptive  condition)  at  least  with  the  influence  of  food  very 
considerably  minimized. 

The  calories  per  kilogram  of  body-weight  for  these  two  children 
(Nos.  139  and  171)  show  a  fall  (as  the  weight  and  age  increase)  quite 
in  conformity  with  that  noted  with  No.  145.  The  calories  per  square 
meter  of  body-surface  for  both  the  children  show  a  maximum  occurring 
from  about  1  year  4  months  to  1^  years,  and  a  tendency  towards  a  fall 
thereafter.  With  No.  171,  for  example,  the  maximum  value  is  1,425 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


125 


calories  per  square  meter  of  body-surface  and  the  minimum  1,053 
calories.  With  No.  139  a  greater  uniformity  is  observed,  the  range 
being  from  1,110  to  864  calories.  The  curve  for  No.  171  is  sharply 
distinguished  from  the  curve  for  No.  145,  in  that  it  shows  an  early 


-No.122(F.)- 


No.119(M.)_ 


No.127(F.)r 


60  1100 

TaW 


7 


-No.138(M.)- 


A 


»ER  SQ 


FIG.  17.— Body-weight,  pulse-rate,  and  basal  heat  production  per  24  hours 
(Nos.  119,  122,  127,  and  138). 

period  of  low  values  for  the  calories  per  square  meter  of  body-surface 
which  does  not  appear  in  the  chart  for  No.  145.  The  pulse-rate,  high 
at  about  1  year,  gradually  falls  off  with  both  Nos.  139  and  171,  and 
fully  confirms  the  observations  drawn  from  the  chart  for  No.  145. 


126     METABOLISM   AND   GROWTH   FROM   BIRTH   TO   PUBERTY. 


Intimate  analysis  of  the  other  20  charts  is  hardly  necessary.  Since, 
however,  the  charts  thus  far  analyzed  show  no  special  values  in  the 
earlier  months  of  life,  at  least  the  physiological  relationships  at  this 
period  should  be  pointed  out.  Attention  is  called  to  the  charts  for 


No.  113(F.)- 


950 

900 
| 

k51°'    450  850 

48     400 «» 
45     350 
300 


X 

X 

/ 

PCEARL£ 

|ra 

/ 

V 

.  — 

— 

—  • 

V 

CALOR 

EoS 

. 

/ 

x* 

OTAL  ( 

ALORIE 

5 

N/ 

^ 

^ 

'''BOG 

Y.  WEIG 

^ 

L  . 

V 

A 

y 

/ 

Cals 
per 
kilo. 
46 

/ 

S/ 

ir 

750500'  43 

\ss- 

SQEM. 

CALOF 

IES  PEI 

KILO^ 

/ 

700450  40 

\ 

/ 

/ 

/X 

2 

X 

11    400  37 

\ 

/ 

/ 

TOTAL 

CALOR 

IES 

Pulse 
10  350100 

N 

/ 

-| 

x 

•  

—  - 

,-^- 

X 

WBE^ 

0 

FIQ.  18. — Body-weight,  pulse-rate,  and  basal  heat  production  per  24  hours 
(Nos.  113,  126,  131,  and  142). 

those  children  with  whom  observations  were  made  at  an  early  age, 
such  as  Nos.  113,  115,  and  119.  (See  figures  17,  18,  and  19, 
pages  125  to  127.)  In  these  charts  the  weight-curve  and  total 
calories  present  the  usual  features,  namely,  progressively  increasing 
weight  and  progressively  increasing  total  calories.  The  increase  in 
the  values  for  the  calories  per  kilogram  of  body-weight  and  per  square 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


127 


meter  of  body-surface  with  an  increase  in  age  is  worthy  of  consider- 
ation. With  No.  115,  for  example,  the  heat  per  kilogram  of  body- 
weight  rises  from  49  calories  at  the  age  of  1  month  to  61  calories  at 
the  age  of  5  months,  the  whole  trend  of  the  curve  being  upwards. 
When  measured  on  the  basis  of  body-surface,  the  heat  is  as  low  as 
765  calories  at  1  month  and  rises  to  1,061  calories  at  the  end  of  5  months. 


No.115(M.)- 


No.136(M.)- 


No.160(F.) 


CALORIES  PER  SQ.  M. 


FIG.  19. — Body-weight,  pulse-rate,  and  basal  heat  productionjper  24  hours 
(Nos.  115,  123,  136,  and  160). 

An  examination  of  other  charts,  such  as  that  for  No.  113  (fig.  18) 
and  those  for  the  younger  children,  shows  similar  general  trends, 
namely,  low  heat  values  on  the  bases  of  body-weight  and  body-surface, 
with  a  gradual  increase  as  the  age  advances  from  7  months  to  1  year. 
Of  special  significance  is  the  fact  that  these  wide  variations  in  the 


128  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

heat  production  per  square  meter  of  body-surface  are  found  with  the 
very  young  children.  This  is  in  conformity  with  variations  observed 
by  us  in  our  studies  of  new-born  children,  in  which  it  was  noted  that 
the  heat  production  per  square  meter  of  body-surface  decreased  at 
times  to  459  calories.1  When  our  early  analysis  of  the  figures  for  the 
heat  production  of  new-borns  was  made,  our  use  of  the  Lissauer 
formula  for  computing  the  body-surface  was  obviously  open  to  some 
criticism.  Subsequently,  as  shown  in  another  section  of  this  report, 
it  was  found  that  the  Lissauer  formula  gives  measurements  agreeing 
admirably  with  those  of  Du  Bois  for  children  weighing  up  to  10  kg. 
During  this  early  period  from  birth  to  6  or  7  months,  the  body-weights 
are  for  the  most  part  under  10  kg.  Hence  we  have  every  reason  to 
believe  that  our  estimates  of  the  heat  production  per  square  meter  of 
body-surface  are  as  close  as  can  possibly  be  made  in  the  present  state 
of  physiological  science. 

The  pronounced  individuality  of  the  children  studied  in  these  longer 
series,  as  evidenced  by  the  fluctuations  in  the  smoothed  curve,  are 
altogether  too  great  to  permit  any  consideration  of  a  normally  pro- 
gressing, increasing  metabolism.  It  is  thus  difficult  to  draw  general 
deductions  from  this  extensive  series  of  charts.  Those  permissible 
are,  first,  the  normally  increasing  body-weight  common  to  all  normal 
children;  second,  the  reasonably  close  paralleling  of  the  total  calories 
with  the  body-weight  curve,  namely,  an  increase  in  total  calories  with 
an  increase  in  body-weight;  third,  the  low  calories  found  on  the  bases 
of  body-weight  and  body-surface  shortly  after  birth,  increasing  to  a 
maximum  not  far  from  one  to  two  years  of  age,  with  a  tendency  for 
a  definite  decrease  thereafter.  Finally,  the  pulse-rate  is  noticeably 
highest  in  the  period  from  birth  to  1  or  1|  years,  with  a  tendency  to 
fall  thereafter.  No  perfect  picture  of  the  general  physiological  trend 
can  possibly  be  made  from  a  visualization  of  these  several  groups  of 
data  for  the  individual  children.  Final  recourse  must  therefore  be 
made  to  our  main  study  of  a  large  number  of  children  of  different  ages, 
weights,  lengths,  and  body-surfaces,  so  as  to  plot  all  values  on  large 
charts  and  thus  study  the  general  trend. 

METABOLISM  DURING  GROWTH  AS  SHOWN  BY  GROUPS  OF 
INDIVIDUAL  DATA. 

In  the  preceding  section  it  has  been  made  clear  that,  with  a  given 
individual,  there  is  no  smoothed  curve  for  metabolism  like  that,  for 
example,  obtained  for  body-weight  with  a  fasting  dog2  or,  indeed,  with 
a  fasting  man.  Daily  basal  metabolism  is  subject  to  very  considerable 
fluctuations,  which  are  nowhere  more  strikingly  shown  than  in  the 
charts  for  individual  children  in  figures  15  to  21.  Plotting  all  the 

1  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  233,  1915,  pp.  96  and  100. 

2  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  203,  1915,  pp.  77  and  75. 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


129 


points  on  the  charts  in  one  scatter-diagram  and  sketching  a  curve 
indicating  the  general  trend  would  obviously  smooth  the  individual 
differences,  not  only  for  the  same  child  from  day  to  day,  but  between 
the  children  studied.  This  we  have  not  done,  but  recognizing  the 
value  of  grouping  all  observations  in  a  series  of  charts  so  as  to  present 
the  general  trend  of  metabolism  of  a  relatively  large  number  of  chil- 


No.172(F.) 


No.173(F.) 


FIG.  20. — Body-weight,  pulse-rate,  and  basal  heat  production  per  24  hours 
(Nos.  148,  161,  172,  and  173). 

dren,  and  thus  visualize  the  influence  of  sex,  age,  weight,  and  surface 
on  metabolism,  we  have  gathered  together  not  only  the  data  from  the 
23  individual  charts  in  figures  15  to  21,  but  also  the  isolated  observa- 
tions on  a  large  number  of  children,  mostly  of  the  higher  ages,  and 
plotted  these  values  in  several  scatter- diagrams.  In  these  diagrams 
the  caloric  output  is  referred  respectively  to  age,  weight,  and  surface 
area  in  a  number  of  ways. 


130  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

In  studying  these  diagrams,  we  may  ask:  Is  the  metabolism  of  a 
child  of  given  height,  age,  and  weight  the  same  as  that  of  another 
child  of  the  same  height,  age,  and  weight?  Are  there  individual 
differences  in  metabolism?  What  is  the  influence  per  se  of  height, 
weight,  age,  and  area  on  metabolism?  What  are  the  sex  differences? 


-No.155(M.) 


No.158(M.)- 


FIG.  21. — Body-weight,  pulse-rate,  and  basal  heat  production  per  24  hours 
(Nos.  153,  155,  158,  and  166). 

All  these  problems  may  only  adequately  be  studied  by  an  intelligent 
comparison  of  extensive  series  of  metabolism  measurements.  The 
individual  curves  show  the  general  relationships  between  growth  and 
metabolism,  but  they  give  information  only  obscurely  and  indirectly 
which  may  be  used  for  a  comparison  of  one  child  with  another  on  the 
basis  of  age,  height,  and  weight,  and  throw  no  light  on  sex  differences. 


METABOLISM   AS   AFFECTED   BY   GROWTH.  131 

When  children  are  considered  as  a  class,  the  gross  differences  in  age, 
weight,  and  stature  make  it  extremely  difficult  to  find  two  children  of 
exactly  the  same  age,  weight,  and  height.  Certainly  any  series  of 
metabolism  measurements  would  have  to  be  greatly  extended  and 
include  a  large  number  of  subjects  to  secure  two  individuals  who  were 
strictly  comparable  in  these  respects.  The  time  and  expense  required 
for  such  measurements  would  prohibit  any  attempt  to  make  sufficient 
studies  with  a  large  number  of  individuals  for  the  establishment  of 
probable  standards  for  the  many  combinations  of  the  four  variables — 
sex,  age,  weight,  and  height.  This  likewise  holds  true  for  adults; 
and  yet  it  is  very  important,  physiologically  at  least,  to  have  some 
conception  of  differences  in  metabolism  with  different  individuals. 

METHOD  OF  GROUPING  DATA. 

Any  plan  for  the  comparative  study  of  the  metabolism  of  children 
involves  one  or  more  forms  of  classification.  Following  the  custom  of 
physiologists,  we  have  charted  the  values  first  on  the  basis  of  age,  then 
of  body-weight,  and  finally  of  body-surface.  Since  with  adults  it  has 
been  clearly  shown  that  there  is  a  sexual  differentiation,  it  seems  desir- 
able to  consider  the  boys  and  girls  separately,  even  though  a  critical 
analysis  of  the  data  for  new-born  babies1  showed  no  sexual  differen- 
tiation during  the  first  week  of  life.  A  comparison  of  the  various 
individual  charts  (figs.  15  to  21),  in  which  the  sex  was  indicated,  or 
even  a  superficial  inspection  of  these  general  charts  (figs.  22  to  47) 
for  boys  and  girls,  gives  but  little,  if  any,  suggestion  of  a  sexual  differ- 
entiation. Such  grouping  is  of  value,  however,  for  use  in  a  more 
thorough  comparison  of  all  the  data  in  several  large  plots  (see  figs. 
48  to  51,  pages  179  to  181),  by  which  the  differences  in  the  results  due 
to  sex  may  be  discerned. 

As  previously  stated  on  page  101,  during  the  period  of  growth 
represented  by  the  observations  in  this  study  there  are  such  rapid 
changes  in  weight  and  age  that  it  has  been  considered  perfectly  legiti- 
mate, when  appreciable  variations  in  these  two  factors  occur,  to  regard 
the  child  as  a  different  individual  and  to  plot  the  values  accordingly 
in  these  group  charts.  In  determining  the  points  on  the  charts  in 
figures  22  to  47,  each  child  was  considered  a  new  individual  after 
(1)  an  increase  in  weight  of  1  kg.  for  children  weighing  less  than  10 
kg. ;  (2)  an  increase  in  weight  of  10  per  cent  for  children  over  10  kg. ; 
(3)  an  increase  in  age  of  6  months.  Change  in  height  per  se  was  not 
considered.  While  the  classification  for  weight  and  age  was  not 
strictly  adhered  to,  there  was  but  little  deviation  from  the  rule.  So 
far  as  possible,  breaks  in  the  continuity  of  evidence  were  avoided,  and 
if  an  observation  was  made  at  the  end  of  a  series,  it  was  not  necessarily 


Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  233,  1915;  Harris  and  Benedict,  Carnegie 
Inst.  Wash.  Pub.  No.  279,  1919. 


132  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

excluded,  even  if  the  full  change  in  weight  or  age  had  not  been  reached. 
It  frequently  happened  that  the  full  change  in  weight  occurred  con- 
siderably inside  of  6  months,  and  there  were  also  instances  when  a 
change  in  age  of  6  months  was  not  accompanied  by  a  full  change  in 
weight.  By  this  method,  certain  children,  notably  No.  145,  appear  a 
number  of  times  upon  the  charts  or  scatter-diagrams.  For  instance, 
in  figure  22,  the  actual  number  of  boys  represented  is  88,  while  the 
number  of  points  plotted  is  129.  These  latter  in  reality  correspond 
to  an  equal  number  of  children,  since  the  values  found  on  the  same 
boy  are  characterized  by  an  appreciable  difference  in  age  or  weight. 

A  biometrical  analysis  of  the  data  in  this  series  of  observations  has 
not  been  attempted,  but  on  each  of  the  group  charts  an  effort  has  been 
made  to  indicate  the  apparent  general  trend  of  the  metabolism  on 
the  basis  selected  for  comparison  by  laying  on  arbitrarily  a  smoothed 
curve.  It  must  be  emphasized  here  that  these  curves  do  not  represent 
mathematically  determined  trends,  but  are  simply  sketched  from 
observation  of  the  general  distribution  of  the  points.  The  curves 
were  prepared  in  the  manner  previously  referred  to  (see  page  37), 
i.  e.,  five  members  of  the  Laboratory  staff,  accustomed  to  plots  and 
curves,  each  drew  on  a  separate  sheet  of  tracing-paper  a  curve  which 
appeared  to  him  as  the  most  probable.  These  curves  were  then  com- 
bined and  the  line  reproduced  on  the  respective  charts  represents  the 
average  of  these  five  plots.  While  this  procedure  is  admittedly  un- 
mathematical,  it  serves  at  least  to  indicate  the  general  trend  of  the 
metabolism. 

All  of  the  precautions  cited  in  our  discussion  of  normality  entered 
into  the  selection  of  the  individuals  and  points  plotted  in  these  group 
charts.  In  a  preliminary  communication  published  elsewhere1  re- 
garding this  study  of  children  during  the  period  of  growth,  a  series  of 
charts  was  given  similar  to  those  in  figures  22,  23,  26,  27,  30,  31,  35, 
36,  42,  43,  45,  and  47.  The  earlier  charts  differed  only  in  the  number 
of  points  included,  which  was  somewhat  greater  than  in  the  present 
series,  as  a  more  rigid  exclusion  of  material  was  made  previous  to  the 
final  printing  here.  A  comparison  of  the  two  sets  of  smoothed  curves 
brings  out  the  interesting  fact  that  those  obtained  in  the  preliminary 
charting  of  the  values,  which  were  prepared  in  much  the  same  manner 
as  the  later  curves,  do  not  differ  by  a  measurable  amount  from  the 
curves  subsequently  sketched  for  the  final  series.  In  other  words, 
the  eliminations  made  exclusively  on  the  basis  of  a  more  critical  exam- 
ination of  the  protocols  and  histories  for  evidence  of  the  normality 
of  the  children  have  resulted  in  the  removal  of  an  approximately  equal 
number  of  points  above  and  below  the  line,  so  that  the  position  of  the 
line  itself  is  not  materially  changed.  This  fact  is  of  considerable 

1  Benedict,  Boston  Med.  and  Surg.  Journ.,  1919,  181,  p.  107. 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


133 


practical  as  well  as  physiological  interest  as  indicating  that,  in  an 
attempt  to  secure  a  more  nearly  perfect  measure  of  normality,  the 
evidence  as  to  the  general  trend  of  the  metabolism  has  not  been 
affected.  One  can  thus,  even  at  this  point,  make  the  deduction  that 
with  the  general  population  as  studied,  the  deviations  above  or  below 
a  central  tendency  are  such  as  to  balance,  and  that  the  influence  upon 
metabolism  of  slight  deviations  from  physical  normality  is  negligible. 

GENERAL  TREND  OF  METABOLISM  WITH  INCREASING  AGE. 
In  this  series  of  group  charts,  the  first  comparisons  have  been  made 
for  the  total  metabolism  as  referred  to  age. 

TOTAL  CALORIES  PER  24  HOURS  REFERRED  TO  AGE    (BOYS). 

The  total  calories  per  24  hours  referred  to  age  for  the  boys  have 
been  charted  in  figure  22.  An  inspection  of  this  chart  shows  a  rapid 
rise  in  the  total  metabolism  during  the  first  year  of  life  and  from  the 


Cals.                                       TOTAL  CALORIES  REFERRED  TO  AGE. 

BOYS. 

1500 
1350 

1200 
1050 
900 
750 
600 
450 
300 
150 
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FIG.  22. — Basal  heat  production  of  boys  per  24  hours  referred  to  age. 
Point  inclosed  in  square  signifies  puberty  established. 

first  to  the  thirteenth  year  a  somewhat  slower  but  steady  increase. 
This  general  trend  seems  to  be  continued  beyond  the  thirteenth 
year;  but  only  three  points  are  available  for  comparison  beyond  this 
age. 

The  interpretation  of  the  sketched  curve  is  beset  with  a  number  of 
difficulties.  In  the  first  place,  the  arbitrary  laying-down  of  a  smoothed 
curve  on  a  plot  of  this  character  gives  too  much  weight  to  the  possi- 
bility of  a  constancy  in  metabolism.  That  this  constancy  is  not 
actually  present  is  clearly  shown  by  the  deviations  from  the  line  all 


134     METABOLISM   AND   GROWTH   FROM   BIRTH   TO   PUBERTY. 

along  the  curve,  particularly  after  8  months  of  age.  It  would  appear 
as  if  the  metabolism  during  the  first  8  months  followed  with  singular 
accuracy  the  direction  of  the  curve.  At  this  point  we  find  the  second 
great  difficulty  in  the  proper  interpretation  of  this  type  of  curve, 
namely,  the  percentage  deviations.  For  example,  at  the  age  of  11 
years,  a  deviation  of  half  a  square  either  side  of  the  curve  corresponds 
to  75  calories,  or,  with  a  basal  metabolism  of  1,125  calories,  a  difference 
of  not  far  from  7  per  cent.  At  the  age  of  6  months  a  like  deviation 
has  exactly  the  same  numerical  value  as  at  11  years,  i.  e.,  75  calories, 
but  on  the  percentage  basis  this  variation  at  6  months  represents  an 
error  of  about  20  per  cent,  since  the  basal  metabolism  is  considerably 
less.  Hence  the  seemingly  close  grouping  of  points  about  the  general 
line  in  the  earlier  years  is  only  apparent  and  does  not  necessarily 
indicate  a  greater  uniformity  in  the  metabolism.  This  particular 
phase  must  be  borne  in  mind  for  all  of  the  charts,  since  it  is  the 
common  custom  of  physiologists  to  consider  deviations  in  metab- 
olism either  side  of  a  so-called  normal  on  the  percentage  basis  and 
these  charts  can  not  be  so  used.  The  chief  usefulness  of  the  chart  in 
figure  22  is  to  indicate  the  tendency  for  the  metabolism  to  increase 
rapidly  during  the  first  year  of  Me  and  to  rise  steadily,  though  not  so 
rapidly,  during  the  remainder  of  youth. 

It  should  be  pointed  out  at  this  juncture  that  two  of  the  three  values 
beyond  the  age  of  13  years  lie  above  the  projected  line.  With  one  of 
these  boys  (13  years  and  8  months  old)  signs  of  puberty  were  very 
clearly  present.1  The  other  two  showed  no  signs  of  puberty.  These 
facts  are  emphasized,  since  subsequent  discussion  of  the  metabolism 
as  influenced  by  puberty  is  necessary,  owing  to  the  great  stress  laid 
upon  this  point  throughout  the  literature,  beginning  with  the  earlier 
studies  of  Andral  and  Gavarret.  Our  data  do  not  permit  the  dis- 
cussion of  the  influence  of  puberty  upon  the  metabolism,  as  the  obser- 
vations did  not  extend  to  this  point,  but  the  accumulation  of  experi- 
mental material  along  this  line  is  now  in  progress  at  the  Nutrition 
Laboratory. 

Neither  is  this  the  time  to  consider  the  possibility  of  predicting  the 
metabolism  of  various  ages  by  referring  to  the  general  curve  or  central 
tendency  for  the  basal  metabolism,  except  as  we  may  lay  down  the 
general  principle  that  as  the  age  increases  the  metabolism  increases, 
and  with  a  reasonable  degree  of  uniformity. 

TOTAL  CALORIES  PER  24   HOURS   REFERRED  TO  AGE    (GIRLS). 

It  is  the  general  opinion  that  boys  as  a  rule  are  much  more  active 
physically  than  girls,  are  less  controllable,  and  can  less  easily  acquire  a 
condition  of  repose.  This  has  a  bearing  upon  any  analysis  of  the 

1  The  values  for  children  showing  evidences  of  puberty  are  represented  on  the  charts  by  en- 
closing the  point  in  a  square.     See  discussion  of  these  values  on  page  183. 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


135 


metabolism  figures  for  boys  and  girls  as  to  sexual  differentiation. 
By  design,  our  observations  included  a  relatively  large  number  of  girls, 
and  therefore  provide  sufficient  points  for  special  chart  treatment. 
The  total  metabolism  of  the  girls  referred  to  age  is  depicted  in  figure  23. 
The  total  number  of  points  is  essentially  the  same  as  for  boys,  and  for 
the  most  part  end  prior  to  puberty.  Beyond  the  age  of  11  years,  the 
values  are  much  scattered  and  but  four  points  are  available.  One 
of  these  points,  that  for  a  girl  12  years  and  1  month  old,  is  the  same 
child  as  that  indicated  by  the  point  for  11  years.  At  both  ages  the 
points  are  specially  designated  for  convenience  in  comparison  of  the 
metabolism  before  and  after  the  establishment  of  puberty.  This 
difference  in  metabolism  is  discussed  in  a  later  section.  (See  page  183.) 


TOTAL  CALORIES  REFERRED  TO  AGE. 


GIRLS. 


1350 
1200 
1050 
900 
750 
600 
450 
300 
150 

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FIG.  23. — Basal  heat  production  of  girls  per  24  hours  referred  to  age. 

Points  inclosed  in  squares  signify  puberty  established.     For  No.  239  compare  point  inclosed  in 
diamond  (prepubescence)  with  point  inclosed  in  square  at  12  years  1  month  (puberty). 

The  sharp  rise  in  the  total  metabolism  in  the  first  year  of  growth  is 
shown  in  figure  23,  as  well  as  the  general  steady  increase  thereafter. 
The  smoothed  curve  does  not  fit  the  points  quite  so  satisfactorily  as 
with  the  boys,  since  between  the  ages  of  2  and  4  years  there  is  clearly 
an  alteration  in  the  general  trend,  which  is  not  noticeable  with  the  boys. 
This  requires  a  slight  alteration  in  the  direction  of  the  line,  but  again 
it  must  be  remembered  that  this  line  is  purely  hypothetical  and  may 
not  be  looked  upon  as  indicating  a  definite  regularity  in  metabolism, 
but  only  the  general  trend. 

While  only  a  superficial  inspection  can  be  given  these  charts  for 
boys  and  girls,  there  seems  to  be  a  general  tendency  for  the  points  to 
group  themselves  somewhat  more  closely  about  the  general  line  with 
the  boys  than  with  the  girls. 


136  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

TOTAL  METABOLISM  OP  CHILDREN  REFERRED  TO  AGE    (EARLIER  INVESTIGATORS). 

Since  our  study  was  made  primarily  to  secure  the  metabolism  under 
conditions  giving  the  basal  metabolism,  i.  e.,  with  the  values  unaffected 
by  muscular  activity  and  with  but  little  and  preferably  no  influence 
of  food,  it  is  important  in  comparing  our  results  with  those  of  earlier 
writers  to  include  of  the  latter  only  those  obtained  under  conditions 
approximating  complete  muscular  repose.  As  shown  in  a  considera- 
tion of  the  previous  literature  on  this  subject  (pages  4  to  21), 
relatively  few  of  the  earlier  values  meet  these  conditions.  For  ex- 
ample, all  the  studies  of  Andral  and  Gavarret1  were  made  with  the 
children  in  the  sitting  position  and  the  data  obtained  (see  table  1, 
page  5)  indicate  a  total  metabolism  per  24  hours  much  higher  at 
the  low  ages  than  that  found  by  us  with  either  boys  or  girls.  Such 
values  of  the  earlier  studies  as  are  suitable  for  comparison  have,  how- 
ever, been  charted,  together  with  the  lines  showing  the  general  trends 
noted  on  our  several  charts. 

The  values  for  the  boy  and  girl  studied  by  Scharling2  can  advan- 
tageously be  plotted,  but  the  data  for  Forster's3  children  are  averaged 
in  such  a  way  that  it  would  be  difficult  to  apply  them  on  our  charts. 
For  example,  he  finds  no  material  change  in  the  carbon-dioxide  pro- 
duction per  10  kg.  with  children  throughout  the  period  from  3  to  7 
years  of  age,  namely,  11.7  grams  per  10  kg.  per  hour,  or  approximately 
3.50  calories  per  kilogram  per  hour.  Since  no  data  as  to  the  body- 
weight  are  given,  it  is  impossible  to  plot  his  values  on  our  charts,  but 
those  given  for  children  from  3  to  7  years  of  age  correspond  to  about  84 
calories  per  kilogram  per  24  hours,  which  is  far  in  excess  of  values 
noted  by  us  for  any  age.  This  high  metabolism  is  made  the  subject 
of  special  discussion  by  Forster. 

Speck's  experiments,4  which  were  made  after  the  ingestion  of  food 
and  with  the  child  in  the  sitting  or  standing  position,  are  also  un- 
suitable for  comparison  with  our  data. 

The  results  of  Sonde"n  and  Tigerstedt's  extensive  series5  for  the  most 
part  can  not  be  employed  here,  with  the  exception  of  the  data  obtained 
with  two  subjects  asleep.  Thus  with  one  boy,  11  years  2  months  old, 
and  with  a  body-weight  of  32  kg.,  the  total  heat  was  1,237  calories 
per  24  hours,  a  value  quite  in  conformity  with  some  points  noted  by  us. 
Another  boy,  12  years  of  age,  showed  a  somewhat  higher  heat  output 
of  1,373  calories. 

1  Andral  and  Gavarret,  Ann.  d.  Chim.  et  d.  Phys.,  1843,  ser.  3,  8,  p.  129. 

2  Scharling,  Ann.  d.  Chem.  u.  Pharm.,  1843,  45,  p.  214;  reprinted  in  detail  in  Ann.  d.  Chim.  et 

d.  Phys.,  1843,  s6r.  3,  8,  p.  478. 
*  Forster,  Amtl.  Ber.  d.  50  Versamml.  deutsch.  Naturf.  u.  Aerate  in  Munchen,  1877,  p.  355; 

also  v.  Ziemssen's  Handbuch  der  Hygiene,  Leipsic,  1882,  1,  p.  76.     See,  also,  Magnus-Levy 

and  Falk,  Archiv  f.  Anat.  u.  Physiol.,  1899,  Suppbd.,  p.  356. 
4  Speck,  Physiologie  des  menschlichen  Athmens,  Leipsic,  1892,  p.  217. 
8  Sonden  and  Tigerstedt,  Skand.  Archiv  f.  Physiol.,  1895,  6,  p.  1. 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


137 


Rubner's  classic  experiments1  unfortunately  give  no  values  which  are 
suitable  for  comparison.  The  data  of  Magnus-Levy  and  Falk2  for 
both  boys  and  girls  are  especially  suitable  for  use  and  have  all  been 
plotted  on  our  charts.  Owing  to  the  extensive  criticisms  applicable 
to  the  work  of  von  Willebrand,3  we  do  not  feel  justified  in  employing 
any  of  his  data  for  comparison  purposes,  although  it  is  not  improbable 
that  certain  scattered  minimum  values  are  normal.  Olin's  experi- 
ments4 were  likewise  made  under  conditions  that  can  not  be  looked 
upon  as  basal.  Finally,  values  have  been  plotted  for  such  of  Murlin 
and  Hoobler's5  children  as  were  strictly  normal,  and  also  the  results 
obtained  in  the  extended  series  of  Du  Bois6  and  his  collaborators  are 
plotted,  although  criticism  has  been  raised  of  these  latter  as  to  the 
selection  of  minimum  periods  and  the  degree  of  muscular  repose. 


TOTAL  CALORIES  REFERRED  TO  AGE. 


1650 
1500 

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FIG.  24. — Basal  heat  production  of  boys  per  24  hours  referred  to  age  (earlier  investigators). 

Comparison  for  boys. — The  points  representing  the  children  studied 
by  us  are  so  numerous  as  to  make  it  unwise  to  reproduce  them  on  the 
same  chart  with  those  obtained  by  former  investigators.  Conse- 
quently, points  for  the  results  found  by  the  earlier  workers  have  been 
plotted  and  the  line  corresponding  to  the  general  trend  shown  in  our 
studies  as  laid  on  the  chart  in  figure  22  has  been  placed  for  comparison 
on  the  chart  in  figure  24,  which  gives  the  results  for  boys.  The 

1  Rubner,  Beitrage  zur  Ernahrung  im  Knabenalter,  Berlin,  1902. 

2  Magnus-Levy  and  Falk,  Archiv  f.  Anat.  u.  Physiol.,  1899,  Suppbd.,  p.  314. 

3  von  Willebrand,  Finska  Lakaresallskapets  Handlingar,  1907,  49,  p.  417. 

4  Olin,  Finska  Lakaresallskapets  Handlingar,  1915,  57,  p.  1434;   also  Skand.  Archiv  f.  Physiol., 

1915,  34,  p.  414. 

6  Murlin  and  Hoobler,  Am.  Journ.  Diseases  of  Children,  1915,  9,  p.  81. 
6  Du  Bois,  Arch.  Internal  Med.,  1916,  17,  p.  887.     Olmstead,  Barr  and  Du  Bois,  Arch.  Internal 

Med.,  1918,  21,  p.  621. 


138  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

striking  feature  of  this  chart  is  that  above  the  age  of  1  year  practically 
all  of  the  earlier  observations  lie  above  the  line,  the  exceptions  being 
two  boys  studied  by  Du  Bois  and  one  boy  observed  by  Magnus-Levy 
and  Falk.  Aside  from  these  three  cases,  the  general  trend  of  metab- 
olism in  practically  all  the  other  studies  was  at  a  noticeably  higher 
level  than  that  found  by  us.  A  number  of  Magnus-Levy's  observa- 
tions lie  very  close  to  our  line;  this  would  seem  to  confute  the  general 
conception  suggested  by  Harris  and  Benedict1  that  the  observations 
of  Magnus-Levy  possibly  indicate  a  racial  difference  in  metabolism. 
From  a  critical  analysis  of  the  earlier  researches  it  would  seem  probable 
that  the  conditions  for  basal  metabolism,  particularly  with  respect 
to  muscular  activity,  were  by  no  means  so  rigidly  adhered  to  in  the 
earlier  observations  as  in  ours,  and  we  believe  that  no  evidence  exists 
thus  far  to  suggest  that  the  differences  in  the  results  may  not  be 
entirely  explained  by  a  difference  in  activity,  without  the  necessity 
of  implying  a  racial  difference  in  the  metabolic  level.  Certainly,  with 
Du  Bois's  data,  we  are  dealing  with  American  material. 


Cals. 


TOTAL  CALORIES  REFERRED  TO  AGE. 


GIRLS. 


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FIG.  25. — Basal  heat  production  of  girls  per  24  hours  referred  to  age  (earlier  investigators). 

Comparison  for  girls. — While  very  few  measurements  of  the  metab- 
olism of  girls  have  been  made,  for  the  sake  of  consistency  we  have 
plotted  in  figure  25  the  few  observations  we  have  been  able  to  find 
in  the  literature  and  have  laid  our  curve  for  girls  upon  the  same  chart. 
We  find  here  two  values  of  Magnus-Levy  below  our  line;  the  other 
values  lie  above  it.  The  two  low  values  of  Magnus-Levy  for  12-year- 
old  girls  are  of  special  interest,  since,  in  the  analysis  of  Magnus-Levy's 
data  made  by  Harris  and  Benedict,2  these  two  girls  had  a  predicted 

1  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  235. 
1  Ibid.,  p.  236. 


METABOLISM   AS   AFFECTED   BY   GROWTH.  139 

metabolism  calculated  with  the  American  normal  (multiple  prediction) 
formula  for  man  that  agrees  remarkably  well  with  that  found,  while 
all  the  other  values  are  much  higher.  With  girls,  therefore,  as  with 
boys,  the  results  of  the  earlier  observations  tend,  in  general,  to  have  a 
higher  level  of  basal  metabolism  than  was  found  in  our  series. 

GENERAL  CONCLUSIONS  AS  TO  TOTAL  METABOLISM  AND  AGE  IN  CHILDREN. 

Our  observations  indicate  a  continually  increasing  metabolism  from 
birth  to  13  years  of  age  with  both  boys  and  girls.  A  slight  deviation 
in  the  general  trend,  as  shown  by  the  hypothetical  smoothed  curves 
laid  on  these  charts,  suggests  that  the  trend  for  girls  is  slightly  different 
from  that  of  boys,  especially  about  the  age  of  2  to  4  years.  No  other 
sexual  differentiation  can  at  this  point  of  the  analysis  be  observed. 

Reference  to  all  the  available  earlier  observations  suitable  for 
comparison  as  basal  measurements  shows  that  for  boys,  save  in  rare 
instances,  the  observations  always  lie  considerably  above  our  line 
representing  the  general  trend.  The  scattered  observations  with  girls 
indicate  substantially  the  same  situation.  From  a  careful  analysis  of 
all  the  earlier  experiments,  we  believe  that  the  results  of  our  observa- 
tions more  nearly  approach  the  true  basal  values  than  those  of  the 
previous  investigations;  hence,  in  lieu  of  further  data,  they  must  be 
looked  upon  as  the  closest  estimates  of  the  true  basal  metabolism  of 
youth  that  have  thus  far  been  obtained. 

TOTAL  METABOLISM  WITH  INCREASING  BOOT-WEIGHT. 

While  physiological  observations  with  children  are  commonly 
referred  to  age,  it  is  particularly  unfortunate  that  the  total  metabolism 
should  be  thus  referred,  for  experience  with  adults  has  shown  us  that 
a  number  of  physiological  factors  play  an  important  role  in  the  total 
metabolism,  among  these  being  body-weight,  stature,  and  age.  Of 
these,  body-weight  has  by  far  the  greatest  influence,  much  greater 
than  that  of  age;  consequently  we  should  more  properly  refer  the 
total  number  of  calories  per  day  to  the  body-weight  rather  than  to 
the  age  of  the  child.  In  general,  the  larger  the  child  is,  one  would 
a  priori  expect  a  greater  metabolism.  Furthermore,  since  we  have 
found  that  the  metabolism  increases  with  age,  and  since  age  and  body- 
weight,  especially  during  the  period  of  growth,  go  more  or  less  hand 
in  hand,  we  should  expect  changes  in  metabolism  to  be  in  reasonable 
conformity  with  changes  in  weight.  Our  curves  representing  the 
relationship  between  total  calories  and  age  may  simply  be  an  ex- 
pression of  the  fact  that  as  children  grow  older  they  likewise  grow 
heavier,  and  the  larger  organism  has  a  larger  heat  production.  Physio- 
logically, therefore,  the  better  method  of  comparison  is  on  the  basis 
of  weight  rather  than  of  age. 


140  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

TOTAL  CALORIES  PER  24  HOURS  REFERRED  TO  WEIGHT   (BOYS). 

In  figure  26  we  have  plotted  for  boys  the  total  calories  per  24  hours 
referred  to  body-weight.  The  general  sweep  of  the  curve  and  the 
dispersion  of  the  points  about  a  central  sketched  line  is  not  unlike 
that  for  boys  for  the  total  calories  referred  to  age.  (See  fig.  22,  page 
133.)  In  fact,  a  superficial  inspection  would  imply  that  of  the  two 
charts  the  points  are  even  more  closely  grouped  about  the  central  line 
in  figure  26.  In  such  comparison  it  should  be  noted  that  the  scales 
in  the  two  charts  are  somewhat  different,  since  each  vertical  division 
in  figure  22  corresponds  to  150  calories,  while  in  figure  26  it  corresponds 
to  but  100  calories. 


Cals. 


TOT  At  CALORIES  REFERRED  TO  WEIGHT. 


BOYS. 


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2      24      26      28      30     32     34      36      38      40     42 

FIG.  26. — Basal  heat  production  of  boys  per  24  hours  referred  to  body-weight. 
Point  inclosed  in  square  signifies  puberty  established. 

The  general  close  agreement  between  the  different  points  and  the 
sketched  central  curve  is  rather  striking,  although  at  times  the  devi- 
ations amount  to  150  or  more  calories.  Thus,  at  19  kg.  one  point 
varies  considerably  over  100  calories  from  the  line,  corresponding  to 
a  deviation  of  15  per  cent.  Another  child,  weighing  38  kg.,  is  180 
calories  below  the  general  line,  while  a  third  child,  weighing  9  kg., 
is  125  calories,  or  25  per  cent,  below  the  central  line.  Similar  instances 
of  values  above  the  line  may  likewise  be  noted.  While  the  child 
designated  as  No.  258,  with  a  weight  of  50.8  kg.,  seems  on  the  chart 


METABOLISM   AS  AFFECTED   BY   GROWTH.  141 

to  have  a  metabolism  differing  widely  from  the  central  tendency,  it 
must  be  remembered  that  if  the  chart  were  extended  to  the  50  kg. 
range,  the  metabolism  would  be  shown  to  be  much  nearer  the  central 
line,  though  still  above  it.  On  the  whole,  the  values  lie  reasonably 
close  either  side  of  the  line;  indeed,  so  close  that  the  use  of  this  curve 
to  predict  the  normal  metabolism  will  be  subsequently  discussed. 
(See  page  188.) 

Attention  should  be  called  to  the  evidence  in  figure  26  of  differences 
in  metabolism,  even  with  children  of  the  same  weight.  In  some 
instances,  i.  e.,  with  children  weighing  38  or  39  kg.,  we  find  a  range 
of  from  1,100  to  1,400  calories,  or  a  difference  of  27  per  cent;  and  at 
21  kg.  we  have  one  value  of  785  calories  and  another  at  985  calories, 
a  difference  of  200  calories,  or  25  per  cent.  At  about  11  kg.  we  have  a 
range  from  450  to  660  calories,  approximately  200  calories,  or  about  45 
per  cent.  Thus  we  see  that  with  certain  individuals  our  extremes 
may  be  fairly  wide.  On  the  other  hand,  the  general  grouping  of  the 
points  around  the  central  line  is  suggestive  of  a  clearly  defined  trend. 

Since  the  general  picture  is  so  similar  to  that  of  the  chart  for  calories 
referred  to  age,  we  apparently  have  here  another  expression  of  the 
fact  that  as  the  children  increase  in  age  they  increase  in  weight,  and 
that  the  age  chart  and  the  weight  chart  are  more  or  less  inseparable, 
since  weight  is  inevitably  correlated  with  age  and  heat  production 
increases  both  with  age  and  weight.  It  would  be  undesirable,  how- 
ever, even  to  imply  that  age  and  weight  are  of  equal  or,  indeed,  of 
comparable  importance  hi  determining  basal  metabolism.  It  has 
been  shown  with  adults  that  there  is  a  definite  influence  of  age,  with, 
on  the  average,  an  actual  decrease  in  the  daily  heat  production  with 
men  of  about  7.15  calories  per  year  and  with  women  a  decrease  of 
2.29  calories  per  year.1  Still,  this  same  analysis  indicates  that  the 
influence  of  weight  far  exceeds  that  of  age;  hence  we  must  conclude 
that  with  children  the  changes  in  metabolism  noted  with  different 
ages  are  due  primarily  not  to  the  age  element,  but  to  the  fact  that  age 
changes  concurrently  with  weight. 

TOTAL  CALORIES  PER  24  HOURS  REFERRED   TO  WEIGHT   (GIRLS). 

The  values  for  the  girls  included  in  this  study  are  charted  hi  figure  27. 
The  line  representing  the  general  trend  of  metabolism  gives  a  picture 
of  rather  rapidly  increasing  metabolism  until  the  weight  of  10  or  12  kg., 
with  a  tendency  thereafter  for  the  metabolism  to  increase  at  a  slower 
rate,  which  is  still  present  when  the  weight  limit  of  the  chart  (39  kg.) 
is  reached.  Practically,  this  chart  should  have  ended  at  the  weight 
of  31  kg.,  there  being  but  two  values  retained  beyond  this  weight. 

The  widest  deviations  of  individuals  from  the  general  line  are,  for 
the  most  part,  well  within  100  calories,  which,  for  the  higher-weight 

1  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  115. 


142  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

ranges,  represents  a  relatively  small  percentage  deviation.  A  com- 
parison ,,of  the  percentage  deviations  for  these  children  with  those 
for  adults  has  special  interest,  since  with  adults  it  was  noted  that 
the  scatter  of  the  individual  points  from  the  central  line  was  very 
considerable.  In  consideration  of  the  rapidly  changing  body-mass 
with  children,  the  compact  arrangement  of  the  points  in  these  charts 
has,  however,  a  somewhat  greater  significance.  With  pronounced 


TOTAL  CALORIES  REFERRED  TO  WEIGHT. 


GIRLS. 


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FIG.  27. — Basal  heat  production  of  girls  per  24  hours  referred  to  body-weight. 
Points  inclosed  in  squares  signify  puberty  established.     For  No.  239  compare  point  inclosed  in 
diamond  (prepubescence)  with  point  inclosed  in  square  at  39.2  kg.  (puberty). 

alterations  in  area,  stature,  and  weight,  such  a  stringent  conformity 
w  the  central  tendency  may  not  be  expected  as  with  well-developed 
adults.  So  close  are  these  points,  on  the  whole,  to  the  general  curves 
for  the  boys  and  girls  that  the  possibility  is  considered  later  of  using 
the  two  curves  for  predicting  the  metabolism  of  children  whose  basal 
heat  output  is  unknown.  (See  page  205.) 

TOTAL  METABOLISM  OF  CHILDREN  REFERRED  TO  "WEIGHT   (EARLIER  INVESTIGATORS). 

The  special  advantages  of  referring  total  metabolism  measurements 
to  weight  rather  than  to  age  observed  with  the  children  in  this  research 
make  it  likewise  important  to  inspect  the  values  reported  by  other 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


143 


investigators  on  this  basis.  We  have  consequently  plotted  in  figure 
28  the  values  for  boys  obtained  by  other  investigators.  For  purposes 
of  comparison  we  have  laid  on  the  smoothed  curve  from  the  chart  in 
figure  26,  representing  the  general  trend  of  the  total  metabolism  of 
boys  as  found  by  us.  With  the  exception  of  one  child  under  6  kg. 
of  weight,  all  of  the  observations  lie  above  the  smoothed  line. 
Since  our  curve  has  been  carried  only  to  42  kg.,  five  of  Du  Bois's 


TOTAL  CALORIES  REFERRED  TO  WEIGHT. 


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kg«.4        6         8       10       12       14      16       18       20     22      24      26      28      30      32     34      36      38      40      42      44      46      48     5 

FIG.  28.  —  Basal  heat  production  of  boys  per  24  hours  referred  to  body-weight 

(earlier  investigators) . 

boy  scouts  and  one  of  Magnus-Levy  and  Talk's  children  are  outside 
of  this  range.  If  the  curve  were  projected,  one  of  these  values 
would  lie  approximately  on  the  line,  another  somewhat  below  it, 
and  four  considerably  above  it.  The  high  values  noted  on  the  basis 
of  weight  for  the  children  studied  by  Magnus-Levy  and  Falk  and  by 
Du  Bois  have  been  criticized,  the  Magnus-Levy  and  Falk  values  by 
Harris  and  Benedict1  and  the  Du  Bois  values  hi  the  historical  section 
of  this  monograph.  (See  page  19.)  The  fact  that  practically  all 
the  values  lie  above  the  general  trend  found  by  us  would  imply  again 
that  our  curve  represents  more  nearly  the  true  basal  value  than  any 
curve  that  can  be  drawn  from  the  earlier  work,  when  the  requirements 
for  basal  conditions  were  apparently  not  so  rigidly  adhered  to. 

1  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  235. 


144  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

Although  but  few  measurements  with  girls  are  available  for  this 
comparison,  they  have  been  plotted  in  figure  29  and  the  corresponding 
curve  derived  from  our  observations  on  girls  has  been  applied.  While 
the  points  all  lie  above  our  curve,  they  are  for  the  most  part  somewhat 
closer  to  the  line  than  was  found  with  the  corresponding  values  for 
boys.  Almost  no  data  are  available  for  girls  at  the  lower  weights. 

Cals.  TOTAL  CALORIES  REFERRED  TO  WEIGHT.  GIRLS- 


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FIG.  29. — Basal  heat  production  of  girls  per  24  hours  referred  to  body-weight 
(earlier  investigators). 

From  an  inspection  of  figures  28  and  29,  it  would  seem  that  the  girls 
as  a  whole  adapt  themselves  more  readily  to  basal  conditions,  especially 
as  to  activity,  than  do  the  boys,  since  our  series  with  girls  more  nearly 
corresponds  with  the  scattered  observations  in  the  earlier  literature 
than  the  comparison  for  the  boys.  The  great  irregularity  in  the  group- 
ing of  points  around  the  curves  when  total  calories  are  referred  to  age, 
which  is  found  in  all  three  charts  on  this  basis,  leaves  no  doubt  that  the 
physiologically  sound  method  of  reference  in  metabolism  measure- 
ments should  be  to  weight  rather  than  to  age,  for,  as  previously 
pointed  out,  although  changes  in  age  and  weight  are  more  or  less 
closely  correlated,  the  predominating  factor  influencing  the  basal 
metabolism  of  the  growing  child  is  undoubtedly  change  in  weight, 
the  change  in  age  influencing  the  metabolism  only  indirectly  as  related 
to  change  in  weight.  The  absence  of  some  age  influence  per  se  is, 
however,  by  no  means  proved. 


METABOLISM   AS   AFFECTED   BY   GROWTH.  145 

METABOLISM  PER  UNIT  OF  BODY- WEIGHT  REFERRED  TO  AGE. 

Since  it  was  early  recognized  that  large  individuals  produce  more 
heat  than  small  ones,  the  comparison  of  metabolism  values  on  the 
basis  of  mass  alone  was  introduced  by  some  of  the  first  investigators. 
Thus,  we  find  that  Forster1  in  his  work  with  children,  expressed  the 
results  obtained  as  metabolism  per  10  kg.  of  weight,  attempting  thereby 
a  rough  grouping  of  all  infants  in  a  10  kg.  class.  From  this  point 
the  step  was  easy  to  consider  all  individuals  on  the  basis  of  per  unit 
of  mass,  and  physiologists  have  since  that  time  had  a  strong  tendency 
to  express  the  values  of  metabolism  for  comparative  purposes  on  the 
basis  of  the  metabolism  per  kilogram  of  body-weight. 

A  biometric  analysis  of  the  metabolism  of  adults  has  shown  that 
weight,  stature,  and  age  have  a  specific  influence  upon  metabolism. 
With  adults,  the  stature  of  an  individual  does  not  appreciably  alter. 
The  age  influence  is  small,  though  definite.  The  weight  changes  are 
considerable,  but  have  rarely  been  studied  with  the  same  individual. 
On  the  other  hand,  with  children  we  have  relatively  great  changes  in 
all  three  factors,  weight,  stature,  and  age,  and  consequently  any  com- 
parative methods  used  for  adults  must  always  be  subject  to  particular 
criticism  when  applied  to  children.  It  is  of  course  physiologically  of 
much  interest  to  compare  the  metabolism  of  a  man  weighing,  say, 
90  kg.  with  that  of  a  man  weighing  45  kg.,  if  only  to  find  the  differ- 
ence in  the  absolute  metabolism,  which  would  naturally  be  assumed  as 
greater  with  the  heavier  individual.  But  physiologists  have  also  long 
sought  for  some  reasonably  definite  relationship  between  the  physical 
characteristics  of  individuals  and  their  metabolism,  the  simplest  of 
these  obviously  being  body-weight.  While  the  problem  is  par- 
ticularly difficult  with  the  age-range  in  our  observations,  it  is  of  as 
great,  if  not  greater,  physiological  importance  to  compare  the  metab- 
olism of  two  children  varying  considerably  in  age  as  it  is  to  compare 
the  metabolism  for  the  two  men.  Thus,  the  average  5-year-old  girl 
weighs  not  far  from  18  kg.,  and  the  average  12-year-old  girl  weighs 
approximately  twice  as  much,  i.  e.,  35  kg.  So  we  have  here  two 
individuals,  one  weighing  twice  as  much  as  the  other,  as  in  the  case 
of  the  two  men. 

Two  bases  for  comparison  have  long  been  used  by  physiologists, 
both  of  which  assume  that  a  definite  relationship  exists  between  total 
metabolism  and  the  physical  characteristic  of  weight  and  total  meta- 
bolism and  the  surface  area  of  the  body.  More  recently  an  entirely 
different  conception  has  been  introduced,  in  that  a  biometric  analysis 
of  the  basal  metabolism  of  a  large  group  of  men  and  women  has 
demonstrated  that  with  each  sex  there  is  a  distinct  correlation  between 
weight  and  metabolism,  between  age  and  metabolism,  and  between 

1  Forster,  Amtl.  Ber.  d.  50  Versamml.  deutsch.  Naturf.  u.  Aerzte  in  Miinchen,  1877,  p.  355; 
also  v.  Ziemssen's  Handbuch  der  Hygiene,  Leipsic,  1882,  1,  p.  76. 


146     METABOLISM   AND    GROWTH   FROM   BIRTH   TO   PUBERTY. 

stature  and  metabolism.  Furthermore,  by  means  of  partial  correla- 
tions, it  has  been  clearly  established  that  each  of  these  factors,  weight, 
stature,  and  age,  has  independent  relationships.  As  pointed  out 
elsewhere,1 

"If  a  group  of  individuals  of  identical  weight  be  examined,  the  taller  in- 
dividuals will  be  found  to  have  the  higher  metabolism.  If  a  group  of  in- 
dividuals of  the  same  stature  be  examined,  the  heavier  individuals  will  be 
found  to  have  the  greater  metabolism." 

In  considering  the  children  observed  by  us,  we  shall  attempt  to 
analyze  the  metabolism  changes  upon  these  various  bases.  That 
which  has  the  earliest  historic  interest  and  has  been  most  persistently 
retained,  perhaps,  is  the  simplest  and  most  obvious  one,  namely, 
that  the  larger  individual  has  the  larger  metabolism;  hence  the 
metabolism  has  been  referred  to  the  unit  of  body-weight  and  com- 
monly expressed  as  the  metabolism  per  kilogram  of  body-weight. 
This  comparison,  unfortunately,  has  the  underlying  assumption, 
which  we  believe  to  be  erroneous,  that  each  kilogram  of  body-weight 
has  the  same  heat-producing  power.  We  know  that  with  a  thin 
man  the  proportions  of  fat,  bone,  and  muscle  differ  greatly  from 
those  with  a  fat  man.  Differences  of  an  even  greater  order  may  be 
noted  when  a  normal,  plump,  healthy  child  is  compared  with  an 
atrophic  child,  and  the  clinician  hopes  to  obtain  from  the  physiological 
studies  such  an  estimate  of  normality  as  to  allow  him  to  make  this 
comparison.  Accordingly,  this  fundamental  assumption  of  equality 
in  the  heat-producing  power  of  the  body-mass,  with  wide  variations 
in  the  composition  of  the  body,  must  always  be  considered  as  subject 
to  severe  criticism.  With  these  mental  reservations,  we  shall  com- 
pare our  children  of  different  weights  and  ages  on  the  basis  of  the 
heat  production  per  kilogram  of  body-weight  and  examine,  in  so  far 
as  the  data  permit,  the  results  obtained  in  the  earlier  studies. 

CALORIES  PER  KILOGRAM  OF  BODT- WEIGHT  PER  24  HOURS  REFERRED  TO  AGE   (BOYS). 

While  the  age  factor  with  adults  has  been  shown  to  have  a  small 
influence,  in  that  the  heat  production  decreases  annually  with  age, 
in  the  period  of  growth  for  boys  it  can  easily  be  imagined  that  the 
influence  of  age  would  be  larger  than  with  adults.  In  comparing  the 
total  heat  production  of  boys  at  different  ages  (see  fig.  22),  it  was 
found  that  age  changes  were  intimately  connected  with  weight  changes, 
but  in  the  comparison  of  the  data  on  the  basis  of  heat  per  kilogram  of 
body-weight,  the  weight  element  is  in  considerable  part  eliminated. 
The  heat  production  per  kilogram  of  body-weight  for  the  boys  studied 
by  us  at  their  various  ages  and  weights  has  been  plotted  in  figure  30, 
and  we  have  here  what  may  properly  be  termed  a  "scatter"  diagram. 

1  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  102. 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


147 


While  a  reasonably  clear  trend  for  the  metabolism  is  shown  in  the 
charts  plotted  on  the  basis  of  total  calories,  it  is  only  with  great  diffi- 
culty that  one  may  discern  a  general  trend  in  figure  30,  which  is  at 
best  only  a  conjecture.  Still,  the  usual  method  was  followed  for 
sketching  this  composite  curve.  The  line  obtained  is  much  more 
irregular  than  any  of  the  curves  thus  far  considered. 


CALORIES  PER  KILO.  REFERRED  TO  AGE.                                  BOYS. 

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FIG.  30. — Basal  heat  production  of  boys  per  kilogram  of  body-weight  per  24  hours 

referred  to  age. 
Point  inclosed  in  square  signifies  puberty  established. 

The  values  for  the  earlier  months  of  life,  as  shown  in  the  chart  in 
figure  30,  indicate  a  clear  tendency  for  a  lower  metabolism  per  kilo- 
gram of  body-weight  than  at  the  end  of  the  first  year,  thus  justifying 
the  upward  trend  of  the  curve.  Subsequent  to  5  years,  the  values 
are  definitely  lower  than  those  in  the  first  3  years  of  life.  Although 
there  is  great  irregularity  in  the  dispersion  of  the  points,  it  was 
thought  best  to  represent  the  trend  after  6  years  by  a  straight  line, 
for  the  irregularity  noted  in  the  distribution  of  the  points  is  perhaps 
no  greater  than  that  found  with  adults.  A  most  careful  analysis 
of  the  material  for  adults  indicated  that  the  straight-line  equation 
gave  as  close  a  representation  of  the  changes  in  metabolism  per  kilo- 
gram of  body-weight  with  changing  years  as  could  be  expressed  by  a 
curve  of  a  higher  order.  Still,  the  laying  on  of  this  curve  must  be 
looked  upon  only  as  an  empirical  representation  of  a  general  trend  and 
not  as  a  mathematically  established  average. 

Of  special  significance  in  this  chart,  therefore,  is  first  the  extra- 
ordinary dispersion  of  the  points  about  the  smoothed  curve.  What- 
ever degree  of  regularity  has  been  heretofore  assumed  by  physiologists 


148  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

in  the  heat  production  per  kilogram  of  body-weight,  the  chart  certainly 
shows  with  children  a  great  diversity  with  age  changes.  The  figures 
indicate  a  somewhat  lower  general  metabolism  per  kilogram  of  body- 
weight  during  the  first  6  months,  with  the  highest  metabolism  per 
kilogram  throughout  the  age-range  of  this  study  to  be  at  1  or  2  years 
of  age.  While  the  values  for  the  period  from  3  to  5  years  are  but  few 
in  number,  they  indicate  a  rather  rapid  fall;  after  the  age  of  5  years 
the  decline  is  definite,  though  not  so  marked.  The  small  number  of 
individuals  studied  over  13  years  of  age  hardly  justifies  a  continuation 
of  this  curve  beyond  that  period. 

The  heat  production  per  kilogram  of  body-weight  has  frequently 
been  considered  as  somewhat  of  a  physiological  constant,  but  we  find 
on  this  chart  a  range  in  values  extending  from  29  to  64  calories  per 
kilogram,  in  other  words,  a  variation  of  over  100  per  cent.  Even 
during  the  first  year  of  life  there  is  a  range  of  from  41  to  64  calories. 
After  the  fifth  year  the  range  is  from  29  to  48  calories.  While  the 
smoothed  curve  laid  on  this  chart  does  imply  a  slight  general  trend, 
there  is  nothing  here  approximating  mathematical  constancy,  and 
certainly  nothing  that  can  be  considered  as  a  physiological  law  estab- 
lishing a  relationship  between  the  heat  production  per  kilogram  of 
body-weight  and  the  age. 

The  charts  comparing  total  calories  do  not  permit  a  comparison  of 
individuals  at  different  weights  or  different  ages;  hence  this  method 
is  of  value,  since  it  supplies  some  suggestion  as  to  the  relative  intensity 
of  metabolism  at  different  ages.  On  the  assumption,  erroneous  though 
it  is,  that  each  kilogram  of  body-substance  has  the  same  heat-producing 
capacity,  one  can  conclude  that  at  the  age  of  1  to  2  years  there  is  a 
greater  relative  intensity  of  metabolism  than  at  any  other  period  of 
life  up  to  13  years,  and  that  the  young  organism  per  unit  of  mass 
produces  a  larger  amount  of  heat  than  does  the  older. 

It  would  appear  from  this  chart  that  with  children  we  are  dealing 
with  physiological  entities  and  not  with  crystalline  structures,  each 
having  its  mathematically  established  planes.  Although  the  method 
of  expressing  the  metabolism  on  the  basis  of  per  kilogram  of  body- 
weight  permits  a  very  gross  comparison  of  different  individuals,  the 
entire  absence  of  uniformity  and  the  wide  scatter  of  the  points  about 
the  central  tendency  show  that  such  comparison  can  have  but  very 
slight  individual  mathematical  significance.  Between  the  ages  of  5 
and  13  years,  although  the  points  are  widely  scattered,  it  would  appear 
as  if  a  straight  line  represented  the  trend  as  well  as  any  other  form  of 
curve.  This  is  of  significance  as  being  preliminary  to  the  straight-line 
tendency  exhibited  with  male  adults,  and  this  curve  therefore  brings 
out  primarily  the  high  metabolism  per  unit  of  mass  noted  with  boys 
at  about  the  age  of  1  to  2  years. 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


149 


CALORIES  PER  KILOGRAM  OF  BODY-WEIGHT  PER  24  HOURS  REFERRED  TO   AGE    (oiBLS). 

Our  observations  on  girls  at  different  ages,  being  practically  as 
numerous  as  those  of  boys,  allow  us  to  study  the  caloric  output  per 
kilogram  of  body-weight  as  referred  to  age.  In  figure  31  we  have 
plotted  the  individual  points  for  all  of  our  girls  on  this  basis.  The 
striking  scatter  of  all  these  points  makes  it  extremely  difficult  to  lay 
on  anything  in  the  nature  of  a  smoothed  curve  that  could  be  considered 
justifiable.  From  the  concensus  of  opinion  of  five  observers,  a  curve 
has  been  sketched  which  indicates  nothing  more  than  a  general  trend. 


Cals. 


CALORIES  PER  KILO.  REFERRED  TO  AGE. 


GIRLS. 


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FIG.  31. — Basal  heat  production  of  girls  per  kilogram  of  body-weight  per  24  hours 

referred  to  age. 

Points  inclosed  in  squares  signify  puberty  established.     For  No.  239  compare  point  inclosed  in 
diamond  (prepubescence)  with  point  inclosed  in  square  at  12  years  1  month  (puberty). 

During  the  first  six  months  on  the  average  there  is  a  somewhat 
lower  metabolism  per  unit  of  weight  than  appears  later,  with  the 
highest  values  occurring  at  about  one  year.  The  general  form  of 
the  curve  is  not  unlike  that  in  figure  30  for  boys.  Although  it  is 
hardly  the  place  to  emphasize  a  sexual  differentiation,  it  is  worth 
while  indicating  here  that  with  boys  the  highest  values  lie  at  64  calories, 
while  with  girls  there  are  six  of  the  individual  points  which  lie  higher 
than  64  calories,  practically  all  of  them  being  inside  the  first  year. 

When  it  is  remembered  that  the  element  of  weight  is  in  large  part 
removed  by  this  comparison,  one  is  impressed  by  the  wide  variations 
to  be  found  in  the  calories  per  kilogram  of  body-weight  of  children  of 
various  ages.  For  example,  at  or  about  the  age  of  1  year  we  find 
variations  ranging  from  42  to  70  calories,  and  it  is  only  after  the  age 


150  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

of  7  years  that  the  individual  points  tend  to  lie  reasonably  close  to  the 
general  smoothed  curve. 

From  the  general  picture  presented  by  the  chart  for  girls,  it  can  be 
seen  that  the  conclusion  drawn  from  that  for  boys  still  holds,  namely, 
that  the  calories  per  kilogram  of  body-weight  exhibit  such  wide  devia- 
tions from  a  general  mean  as  to  make  it  impossible  to  conceive  of 
anything  approximating  a  physiological  law  associating  the  heat 
production  per  kilogram  of  body-weight  with  the  age.  The  scattering 
of  the  points  makes  the  laying-on  of  this  smoothed  curve  a  distinct 
violation  of  mathematics  and  open  to  severe  criticism.  We  wish 
again  to  emphasize  that  the  curves  on  all  of  these  charts  are  not  to 
be  interpreted  on  the  basis  of  mathematical  accuracy,  but  simply  to 
indicate  the  central  tendency  and  general  trend. 

CALORIES  PER  KILOGRAM  OF  BODY-WEIGHT  PER  24  HOURS  REFERRED  TO  AGE  (EARLIER 

INVESTIGATORS)  . 

Since  the  measurement  of  the  metabolism  per  unit  of  mass  plays 
such  an  important  role  with  the  earlier  writers,  the  comparatively  few 
individual  values  found  by  other  investigators  with  boys  are  plotted 
in  figure  32.  On  this  chart  we  have  likewise  laid  our  general  line 


Gals. 


CALORIES  PER  KILO.   REFERRED  TO  AGE. 


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fn.     1        234        56        7        8       9       10       11       12      13      14      15     16 

FIG.  32. — Basal  heat  production  of  boys  per  kilogram  of  body-weight  per  24  hours 
referred  to  age  (earlier  investigators). 

from  figure  30.  With  the  single  exception  of  one  value  at  the  age  of 
2  months,  no  other  point  in  the  entire  series  lies  below  our  general 
line  up  to  the  age  of  13  years,  but  for  the  most  part  they  lie  very  con- 
siderably above  our  line.  Beyond  13  years  two  points  obtained  by 


METABOLISM   AS   AFFECTED   BY   GROWTH.  151 

Du  Bois  with  boy  scouts  in  his  second  series  of  experiments  indicate 
values  a  little  below  our  projected  general  trend. 

This  comparison,  in  which  the  influence  of  variations  in  weight  is  in 
part  eliminated,  still  shows  that  practically  all  of  the  values  obtained 
in  the  earlier  work  are  on  a  higher  metabolic  level  than  ours.  We  are 
thus  forced  to  the  conclusion  that  much  of  the  earlier  work  was  un- 
wittingly affected  by  muscular  activity  to  such  an  extent  that  it  fails 
to  meet  modern  requirements  for  basal  metabolism  measurements. 
Still,  the  general  trend  of  the  earlier  work  is  not  widely  different  from 
that  observed  in  our  research,  for  a  smoothed  curve  passed  through 
the  points  on  the  chart  hi  figure  32  would  be  of  approximately  the 
same  order,  although  at  a  higher  level  than  that  shown  by  our  results. 
This  suggests  that  the  differences  in  the  various  series  of  observations 
are  due  wholly  to  differences  in  the  degree  of  approximation  to  basal 
conditions.  The  earlier  work  does  not,  however,  bring  out  the  dis- 
tinctly lower  metabolism  in  the  first  few  months  of  life  which  is  so 
clearly  shown  by  the  general  averages  of  our  more  numerous  data. 

The  relatively  few  observations  of  earlier  writers  on  girls  make  it 
seemingly  unnecessary  to  burden  this  report  with  a  reproduction  of 
an  additional  chart  comparing  the  values  per  kilogram  of  body-weight 
referred  to  age  for  these  investigators.  It  is  sufficient  to  state  that 
all  of  the  earlier  values  lie  above  our  smoothed  curve,  with  the  excep- 
tion of  two  of  Magnus-Levy  and  Falk's  girls  at  11  and  12  years,  both 
of  which  lie  but  little  below.  The  points  for  the  Magnus-Levy  and 
Falk  girls,  however,  are  grouped  about  the  curve  with  a  distribution 
not  dissimilar  to  that  for  our  own  values.  In  general,  all  the  girls 
previously  measured  who  were  10  years  of  age  and  over  show  a  reason- 
ably close  agreement  with  our  smoothed  curve  on  the  basis  of  calories 
per  kilogram  of  body-weight. 

The  importance  of  studying  the  metabolism  during  youth  was 
clearly  emphasized  in  the  classical  studies  of  Sonde"n  and  Tigerstedt,1 
but  owing  to  the  absence  of  conditions  prerequisite  for  the  determina- 
tion of  basal  metabolism,  the  values  are  not  strictly  comparable  and 
only  two  could  be  used  in  the  chart  in  figure  32.  We  have,  however, 
selected  minimum  carbon-dioxide  periods  and  computed  the  minimum 
calories  per  kilogram  referred  to  age;  these  are  plotted  in  figure  33 
for  boys.  Upon  the  same  chart  we  have  laid  our  curve  for  basal 
metabolism  of  boys  from  7  to  16  years  and  likewise  included  the  values 
recently  cited  by  Carl  Tigerstedt2  for  boys  from  9  to  14  years  of  age. 
This  last  citation  is  preceded  by  a  careful  statement  as  to  the  im- 
portance of  muscular  rest,  and  these  values  have  accordingly  been 

1  Sonden  and  Tigerstedt,  Skand.  Archiv  f.  Physi<51.,  1895,  6,  p.  1. 

5  Tigerstedt,  Carl,  Ueber  die  Nahrungszufuhr  des  Menschen  in  ihrer  Abhangigkeit  von  Alter, 

Geschlecht  und  Beruf,  Helsingfors,  1915.     See  also  Skand.  Archiv  f.  Physiol.,  1916,  34, 

p.  151. 


152  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


selected  with  this  in  mind.     Similar  results  are  shown  in  figure  34 
for  girls. 


Cals 
72 

68 
64 
60 
56 
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44 
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32 
28 

CALORIES  PER  KILO.  REFERRED  TO  AGE.                                   BOYS. 

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FIG.  33. — Basal  heat  production  of  boys  per  kilogram  of  body-weight  per  24  hours  referred 

to  age  (Sonde"n  and  Tigerstedt,  C.  Tigerstedt,  and  Benedict  and  Talbot). 
The  two  crosses  represent  the  values  found  by  Sonden  and  Tigerstedt  with  boys  during  sleep. 


Cals. 
72 

68 
64 
60 
56 
52 
48 
44 
40 
36 
32 
28 

CALORIES  PER  KILO.  REFERRED  TO  AGE.           GIRLS. 

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10       11        12      13      14       15       16      17      18 

FIG.  34. — Basal  heat  production  of  girls  per  kilogram  of  body-weight  per  24  hours 
referred  to  age  (Sonden  and  Tigerstedt,  and  Benedict  and  Talbot). 

The  striking  feature  of  these  charts  is  the  great  difference  between 
the  values  reported  by   Sond6n  and  Tigerstedt   and  those  in  our 


METABOLISM   AS   AFFECTED   BY   GROWTH.  153 

smoothed  curves.  Of  importance,  however,  is  the  fact  that  the 
values  obtained  by  Sonden  and  Tigerstedt  with  two  sleeping  boys 
11  and  12  years  old,  respectively,  and  indicated  in  figure  33  by  small 
crosses,  lie  close  to  our  line.  This  explains  not  only  why  our  values 
are  lower  than  the  other  values  found  by  Sonden  and  Tigerstedt,  as 
well  as  the  composite  values  derived  by  Carl  Tigerstedt  from  the 
observations  of  Hellstrom,  Rubner,  von  Willebrand,  and  Sonde"n  and 
Tigerstedt,  but  likewise,  we  believe,  why  they  are  lower  than  the 
results  of  the  observations  of  Magnus-Levy  and  Falk,  Du  Bois,  and 
others.  When  the  experimental  conditions  under  which  the  early 
investigations  were  made  more  nearly  approach  basal  requirements 
the  values  are  found  to  be  more  in  line  with  our  smoothed  curve.  As 
will  be  seen  later  (page  209),  while  we  must  disregard  in  large  measure 
the  earlier  work  as  a  standard  for  basal  metabolism,  these  results 
have  a  great  practical  value  for  estimating  the  probable  24-hour  total 
daily  requirements  of  the  growing,  active  child.  The  two  series  thus 
supplement  each  other  perfectly. 

METABOLISM  PER  UNIT  OF  BODY-WEIGHT  REFERRED  TO  WEIGHT. 

In  referring  the  metabolism  of  children  to  age,  undue  stress  is  laid 
upon  the  age  element;  from  the  earlier  analysis  of  the  metabolism  of 
adults  of  different  ages,  we  have  every  reason  to  believe  that,  while 
the  age  factor  is  by  no  means  to  be  ignored,  it  does  not  hi  any  way 
compare  with  the  weight  factor.  With  youth,  gross  differences  in 
metabolism  are  noted  with  variation  in  age,  but  these  differences  may 
in  large  part  be  ascribed  to  the  concomitant  weight  changes,  since  a 
child  changing  in  age  is  likewise  changing  in  weight.  Theoretically, 
at  least,  a  more  logical  comparison  of  the  metabolism  of  different 
children  is  not  upon  the  basis  of  age,  but  upon  weight.  The  weight 
element  is  in  part  removed  by  computing  the  calories  per  kilogram  of 
body-weight.  Even  then,  strictly  speaking,  the  comparison  still  is 
best  made  with  children  of  various  weights  rather  than  of  various 
ages.  From  the  analysis  of  the  charts  in  figures  22  to  32,  it  is  seen 
that  in  general  the  pictures  of  the  metabolic  changes  for  the  various 
weights  are  not  unlike  those  for  age,  and  hence  we  are  prepared  to  find 
the  curves  for  the  calories  per  kilogram  of  body-weight  referred  to 
body-weight  somewhat  similar  to  those  in  which  these  values  are 
referred  to  age. 

Our  values  for  boys  have  been  plotted  in  figure  35  and  a  smoothed 
curve  sketched  to  indicate  approximately  the  general  trend.  The 
very  wide  scatter  of  the  points,  particularly  below  18  kg.  in  weight, 
is  worthy  of  special  notice  and  is  fully  in  accordance  with  variations 
noted  in  the  age  charts.  It  seems  reasonably  clear  that  at  the  weights 
under  6  or  7  kg.  there  still  is  a  tendency  for  the  metabolism  to  be 
somewhat  lower  per  kilogram  than  a  little  later.  Hence  we  feel  that 


154  METABOLISM  AND  GROWTH  PROM  BIRTH  TO  PUBERTY. 

the  rise  in  the  sketched  curve  is  perfectly  justifiable.  The  maximum 
occurs  at  about  7  or  8  kg.,  this  approximating  the  average  weight  for 
children  of  one  year.  Thence  the  curve  decreases  with  a  reasonable 
degree  of  regularity.  Not  until  24  kg.  and  over  is  reached  do  the 
points  lie  sufficiently  close  to  the  central  line  to  give  a  clear  idea  of 
physiological  regularity  in  the  metabolism  per  kilogram  of  body- 
weight  referred  to  the  total  weight. 


Cate. 


CALORIES  PER  KILO.  REFERRED  TO  WEIGHT. 


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8       10      12      14       16       18      20     22     24     26     28      30     32     34     36     38      40     42 

FIG.  35.— Basal  heat  production  of  boys  per  kilogram  of  body-weight  per  24  hours 

referred  to  weight. 
Point  inclosed  in  square  signifies  puberty  established. 

The  suggestion  of  sexual  differentiation  between  boys  and  girls, 
even  at  the  early  ages,  noted  in  the  calories  per  kilogram  at  the  age 
of  one  year,  makes  it  desirable  to  consider  by  itself  the  metabolism 
per  kilogram  of  the  girls  at  different  weights.  These  values  are  plotted 
on  the  chart  in  figure  36,  together  with  our  smoothed  curve  indicating 
the  general  trend  of  metabolism.  The  most  pronounced  feature  of 
this  chart  is  the  wide  scatter  of  the  individual  points  from  the  smoothed 
curve,  this  being  even  more  evident  for  the  girls  than  for  the  boys. 
Still,  it  is  reasonably  clear  that  the  general  trend  shows  a  rise  between 
3  and  8  kg.,  where  the  maximum  is  found,  with  a  clearly  defined 
decrease  thereafter  to  about  26  kg.  Subsequent  to  that  point  the 
line  appears  to  be  reasonably  level,  but  the  number  of  points  available 
beyond  30  kg.  is  so  few  as  hardly  to  justify  discussion.  Up  to  18  kg. 
there  is  such  a  wide  dispersion  of  points  about  the  smoothed  curve 
that  no  conclusion  may  be  drawn  regarding  a  physiological  law,  even 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


155 


though  the  general  trend  seems  to  be  established  with  reasonable 
clearness.  The  correlation  between  the  calories  per  kilogram  and  the 
body-weight  is  not,  therefore,  a  very  striking  one.  While  it  is  suf- 
ficient to  indicate  a  low  metabolism  at  the  early  weights,  with  a  rise 
to  a  maximum  at  about  8  kg.,  so  far  as  the  individual  is  concerned 
one  can  not  predict  at  the  weight  range  of  6  to  8  kg.  whether  the 
metabolism  will  be  43  or  70  calories  per  kilogram.  After  18  kg.  there 
seems  to  be  a  reasonable  degree  of  compactness  in  the  grouping  of  the 
individual  points. 


Cals. 


CALORIES  PER  KILO.  REFERRED  TO  WEIGHT. 


69 
66 
63 
60 
57 
54 
51 
48 
45 
42 
39 
36 
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kgs.  4       6         8       10       12      14       16       18      20      22     24      26      28     30     32      34      36      38     4( 

FIG.  36. — Basal  heat  production  of  girls  per  kilogram  of  body-weight  per  24  hours 

referred  to  weight. 

Points  inclosed  in  squares  signify  puberty  established.     For  No.  239  compare  point  inclosed  in 
diamond  (prepubescence)  with  point  inclosed  in  square  at  39.2  kg.  (puberty). 

At  the  same  weights,  very  great  differences  in  metabolism  are  noted 
in  both  figures  35  and  36,  even  with  the  unit  here  employed,  namely, 
the  calories  per  kilogram  of  body-weight.  It  is,  however,  clearly 
established  from  both  curves  that  the  metabolic  activity  per  unit  of 
weight  is  very  much  greater  at  the  lower  weights  than  at  the  higher. 
This  is  in  full  conformity  with  the  experience  with  adults,  the  heavy 
individuals  having  a  lower  heat  production  per  kilogram  of  body- 
weight  than  the  light  men  and  women.  A  popular  interpretation  of 


156  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

this  phenomenon  with  adults  has  been  that  with  the  heavy  individuals 
there  is  a  large  proportion  of  inactive  fat,  which  does  not  materially 
contribute  to  the  heat  production.  This  explanation,  while  reasonably 
clear  for  adults,  does  not,  we  believe,  hold  true  with  children,  for  on 
this  basis  we  should  expect  the  children  with  the  higher  weights  to 
have  a  much  larger  proportion  of  inactive  body-fat  than  the  smaller 
younger  children,  and  in  consequence  their  heat  production  per  kilo- 
gram of  body-weight  would  be  lower.  As  a  matter  of  fact,  physical 
examination  has  shown  that  young  children  usually  have  a  much 
larger  proportion  of  fat  than  older  children,  so  that  the  phenomenon 
exhibited  in  figures  35  and  36  is  exactly  contrary  to  what  would  be 
expected  if  one  considered  solely  the  proportion  of  fat  in  the  body. 
At  this  point  a  note  of  caution  must  be  sounded.  In  our  discussion 
of  the  conditions  laid  down  by  us  as  the  basal  requirements,  we  have 
stressed  considerably  the  fact  that  with  young  children  one  of  the  pre- 
requisites for  basal  measurements  can  not  be  satisfactorily  met,  i.  e., 
the  post-absorptive  condition.  With  adults,  measurements  are  made 
approximately  12  hours  after  the  last  meal,  when,  it  has  been  experi- 
mentally demonstrated,  the  stimulus  of  the  previously  ingested  food 
has  practically  disappeared.  Our  observations  show  that  the  younger 
the  children,  the  more  difficult  it  is  to  secure  long  periods  without  food. 
Furthermore,  with  young  children,  particularly,  it  is  difficult  to  deter- 
mine exactly  at  what  hour  the  stimulus  of  the  previously  ingested 
food  ceases  and  the  point  at  which  the  stimulus  of  the  ever-occurring 
incipient  acidosis  begins.  Since  the  influence  of  the  previously 
ingested  food  is  in  inverse  proportion  to  the  age  of  the  children  in- 
cluded in  this  study,  one  must  bear  in  mind  that  the  high  portion 
shown  in  both  curves  in  the  two  figures  35  and  36  is  undoubtedly  in 
part  influenced  by  the  previous  ingestion  of  food.  We  believe,  how- 
ever, that  if  a  correction  were  possible  for  the  influence  of  food,  on 
the  percentage  basis  this  part  would  still  lie  somewhat  above  that 
for  the  older  and  heavier  children.  Furthermore,  we  have  every 
reason  to  believe  that  the  values  observed  at  the  earlier  weights  (from 
3  to  5  kg.)  were  fully  as  much  affected  by  the  previous  food  as  those 
between  6  and  8  kg.,  and  there  is  clear  evidence  of  a  somewhat  lower 
metabolism  at  these  weights.  While,  therefore,  the  previous  ingestion 
of  food  unquestionably  raises  somewhat  the  level  of  the  curve  showing 
the  general  trend  of  metabolism  per  kilogram  of  body- weight,  probably 
no  theoretical  correction  could  remove  all  of  this  difference,  especially 
as  we  have  likewise  a  somewhat  compensatory  effect  due  to  the  fact 
that  many  of  our  younger  children  were  in  deep  sleep,  a  condition 
that  we  believe  definitely  lowers  the  metabolism.  So  while  our 
children  could  not  be  compared  on  the  basis  of  a  "  post-absorptive 
condition"  with  adults,  for  the  most  part  they  were  asleep  and  had 
a  somewhat  lower  metabolism  due  to  the  specific  effect  of  sleep  than 
did  the  adults,  who  were  for  the  most  part  awake. 


METABOLISM   AS   AFFECTED    BY   GROWTH. 


157 


CALORIES  PER  KILOGRAM  OF  BODY-WEIGHT  PER  24  HOURS  REFERRED  TO  WEIGHT  (EARLIER 

INVESTIGATORS)  . 

The  general  trend  of  the  calories  per  kilogram  of  body-weight 
referred  to  weight  may  be  compared  with  the  individual  points  noted 
by  other  observers.  This  has  been  done  for  boys  in  figure  37  for  the 
weight  ranges  up  to  43  kg.  To  avoid  enlarging  this  chart  unduly, 
it  was  necessary  to  omit  a  number  of  values  obtained  by  Du  Bois  and 
published  in  the  second  paper  on  his  studies  with  boy  scouts.1  The 

Cals.  CALORIES  PER  KILO.    REFERRED  TO  WEIGHT.  BOYS. 


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FIG.  37. — Basal  heat  production  of  boys  per  kilogram  of  body-weight  per  24  hours 
referred  to  weight  (earlier  investigators). 

TABLE  29. — Values  outside  weight  range  in  figure  37  (Du  Bois). 


Heat  per 

Subject. 

Weight. 

kilogram  per  24 

hours. 

kilos. 

cals. 

R    M                                       

49.1 

26.6 

R    F                                           

48.6 

29.3 

H  B                                  

49.1 

31.9 

H.  K  

49.3 

32.4 

four  boys  who  were  outside  of  the  weight-range  studied  by  us  gave 
the  values  shown  in  table  29. 

Aside  from  the  values  in  table  29  and  the  infant  of  5.5  kg.  shown 
on  the  chart,  all  the  points  lie  very  considerably  above  our  smoothed 
curve.  If  an  approximate  line  were  to  be  laid  through  these  earlier 
values,  it  would  follow  with  reasonable  regularity  at  a  higher  level 

1  Olmstead,  Barr  and  Du  Bois,  Arch.  Internal  Med.,  1918,  21,  p.  621. 


158  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

that  laid  down  from  our  observations.  It  therefore  seems  clear, 
from  all  observations,  that  the  metabolism  per  unit  of  body-mass  is 
noticeably  higher  at  6  to  8  kg.  of  weight  than  at  any  other  time  of  life. 
Our  curve  indicates  that  the  metabolism  is  lower  from  3  to  5  kg.  than 
from  6  to  8  kg.,  but  this  is  not  shown  by  the  earlier  work.  The  gradual 
fall  from  8  to  42  kg.,  at  which  point  our  observations  end,  is  also 
apparent  in  all  the  observations.  From  the  comparison  of  the  calories 
per  kilogram  of  body-weight  in  all  the  series,  the  general  picture  is 
thus  essentially  the  same,  and  the  newer  data  simply  extend  and 
confirm  the  earlier  observations.  The  striking  feature  of  this  com- 
parison is  that  the  new  work  shows  a  distinctly  lower  level  all  along 
the  line  and  brings  out  the  lower  metabolism  during  the  first  few 
months  of  life. 

The  scarcity  of  earlier  material  available  for  comparison  does  not 
justify  publishing  here  a  chart  for  girls,  but  such  a  comparison  has 
been  made.  Two  of  the  values  obtained  by  Magnus-Levy  and  Falk 
for  girls  weighing  between  40  and  42  kg.  lie  but  little  above  our  curve. 
In  general,  the  points  for  girls  up  to  40  kg.,  though  above  our  line, 
lie  fairly  close  to  it,  and  are  not  more  widely  scattered  than  our  own 
observations.  The  number  of  points  is  so  small,  however,  that  they 
give  no  suggestion  of  a  general  trend,  but,  so  far  as  they  go,  they  are  in 
fair  conformity  with  our  curve  and  indicate  a  higher  metabolism  at 
the  lower  weights. 

Notwithstanding  the  objections  raised  in  earlier  paragraphs  regard- 
ing the  probable  influence  of  food,  the  evidence  in  all  the  observations 
demonstrates  that  there  is  a  profound  physiological  difference  in  the 
metabolism  of  children  weighing  6  to  8  kg.  from  that  obtaining  at  any 
other  period  of  life.  If  correction  could  be  made  for  the  composition 
of  the  body,  it  would  appear  that  (per  unit  of  weight  of  body-material 
other  than  fat)  the  metabolism  would  be  even  greater  at  the  early 
weights  and  that  undoubtedly  with  these  weights  (6  to  8  kg.)  there  is 
greater  metabolic  intensity  per  unit  of  active  protoplasmic  tissue  than 
at  any  other  point  in  the  life  of  youth. 

In  an  earlier  report1  we  emphasized  the  extraordinarily  low  heat 
production  of  new-born  infants,  particularly  on  the  first  day  of  birth, 
attributing  this  in  part  to  the  temperature  changes  and  perhaps  weak 
condition  of  the  organism  after  the  birth  and  bath.  It  would  seem 
as  though  this  lower  metabolism  is  characteristic  of  very  young 
children  and  that  the  metabolism  per  unit  of  mass  gradually  increases 
until  about  the  age  of  1  year,  or  a  weight  of  6  to  8  kg.,  and  thereafter 
steadily  declines  throughout  the  period  of  youth. 

1  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  233,  1915,  pp.  103  and  118. 


METABOLISM   AS   AFFECTED   BY   GROWTH.  159 

RELATIONSHIP  BETWEEN  SURFACE  AREA  OF  THE  BODY  AND  METABOLISM. 

For  decades  the  surface  area  of  the  body  has  by  many  physiologists 
been  considered  to  have  an  intimate  (in  fact,  a  determining)  relation- 
ship with  the  heat  production.  An  extensive  critique1  of  the  body- 
surface  law  makes  it  unnecessary  here  to  do  more  than  to  summarize 
in  the  following  manner : 

Height  and  weight  have  independent  influences  upon  metabolism; 
body-surface,  with  its  rather  close  relationship  to  weight,  likewise 
has  an  apparent  relationship  to  metabolism.  Since  body-surface 
represents  more  nearly  a  general  morphological  law  of  growth  than 
body-weight  does,  the  relationships  between  accurately  measured 
body-surface  and  metabolism  are  frequently  much  closer  than  between 
body-weight  and  metabolism.  Biometric  analysis  has  shown,  how- 
ever, that  certainly  with  the  older  methods  of  estimating  body-surface, 
namely,  the  Meeh  formula  with  its  several  constants,2  body-weight 
and  body-surface  are  equally  closely  correlated  with  heat  production. 
When  more  exact  methods  for  estimating  body-area  are  used,  par- 
ticularly the  linear  formula  and  the  resultant  height-weight  chart  of 
Du  Bois,3  the  correlation  between  area  and  metabolism  is  slightly 
better  than  that  between  weight  and  metabolism,  particularly  if  the 
method  employing  regression  equations  suggested  by  Harris  and 
Benedict4  be  employed.  The  earlier  estimates  of  body-surface  area 
(from  the  Meeh  formula)  are  so  erroneous  and  the  factors  have  such 
large  coefficients  of  variation  that  at  best  they  are  only  rough  approx- 
imates, and  the  modern  physiologist  may  well  disregard  completely 
all  consideration  of  body-surface  as  calculated  from  the  Meeh  formula. 

The  freeing  of  physiology  from  the  cumbersome,  wholly  erroneous 
method  of  Meeh  is  due  to  the  admirable  work  of  D.  and  E.  F.  Du  Bois,5 
who,  by  an  extensive  series  of  painstaking  measurements  of  surface 
and  casts  from  the  surface  of  the  body,  have  established  a  method  of 
estimating  the  surface  area  of  the  body  with  a  very  considerable  degree 
of  accuracy.  This  method  agrees  perfectly  with  an  entirely  different 
method  of  measurement  based  upon  a  photographic  procedure.6  It' 
should  be  stated,  however,  that  the  photographic  method  could  not 
have  been  developed  without  the  work  of  the  Du  Boises.  As  a  result 
of  the  critique  of  the  body-surface  law  presented  by  Harris  and  Bene- 
dict, we  believe  that  the  accurate  measurements  of  body-surface  made 
possible  by  Du  Bois  may  legitimately  be  used  in  a  manner  heretofore 
never  practicable  in  metabolism  experiments,  provided  that  they  are 
considered  as  physical  measurements  and  with  no  erroneous  concep- 

1  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  129. 

z  Meeh,  Zeitschr.  f.  Biol.,  1879,  15,  p.  425. 

« Du  Bois  and  Du  Bois,  Arch.  Intern.  Med.,  1916,  17,  p.  863. 

<  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  188. 

6  Du  Bois  and  Du  Bois,  loc.  cit. 

6  Benedict,  Am.  Journ.  Physiol.,  1916,  41,  p.  275. 


160  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

tions  as  to  the  existence  of  a  causal  relationship  between  surface-area 
and  heat  elimination. 

Nearly  all  of  our  records  of  the  surface  areas  of  the  children  in  this 
research,  especially  those  for  children  above  1  year  of  age,1  are  based 
upon  actual  measurements  of  the  surface-area  by  the  Du  Bois  linear 
formula,  and  hence  represent  true  physical  measurements  rather  than 
computations  from  body-weight,  which  so  long  supplied  the  only 
basis  for  body-surface  estimates.  With  our  children,  therefore,  this 
accurately  determined  physical  measurement  may  legitimately  be 
employed  exactly  as  we  used  the  body-weight;  if  we  so  chose,  we 
could  likewise  use  the  stature.  Since  the  preponderance  of  evidence 
is  slightly  in  favor  of  the  correlation  between  body-surface  accurately 
measured  and  basal  metabolism  on  the  one  hand,  and  body-weight  and 
basal  metabolism  on  the  other,  a  comparison  of  the  surface-area  and 
total  metabolism  is  of  physiological  interest. 

For  practical  use  it  is  highly  desirable  to  determine  a  normal  trend 
of  basal  metabolism  referred  to  some  simply  measured  factor,  such 
as  weight,  for  the  purpose  of  predicting  the  heat  production  of  a  subject 
whose  weight  is  known  but  whose  metabolism  has  not  been  measured. 
The  multitudinous  measurements  involved  in  the  Du  Bois  linear  for- 
mula may  therefore,  in  many  instances,  rule  out  the  possibilities  of 
comparing  the  measured  surface-area  and  the  total  metabolism,  or 
using  the  measured  surface-area  as  a  unit  for  estimating  basal  meta- 
bolism, as  has  so  long  been  attempted  from  either  body-weight  or 
from  the  surface-area  as  computed  by  the  Meeh  formula. 

In  discussing  our  values  on  the  basis  of  body-surface,  it  should  be 
emphasized  again  that  body-surface  must  be  looked  upon  simply  as  a 
physical  measurement  approximating  perhaps  more  closely  the 
general  morphological  law  of  growth  than  does  body-weight,  and 
hence  by  this  very  fact,  perhaps,  giving  a  somewhat  better  idea  of 
the  relationship  between  the  mass  of  active  protoplasmic  tissue  and 
heat  production  than  would  the  weight  alone.  We  believe  there  is 
no  causal  relationship  between  body-surface  area  and  heat  production. 
All  of  our  experimental  evidence,  not  only  for  children  but  for  adults 
under  various  conditions  of  nutrition,  implies  that  the  production  of 
heat  in  the  body  is  not  determined  by  the  loss.  Even  if  it  were  granted, 
for  the  sake  of  argument,  that  the  reverse  is  true,  the  physical  and 
physiological  factors  influencing  the  heat  loss  from  the  surface  of  the 
human  body  are  so  different  at  different  parts  of  the  body  as  to  pre- 
clude any  generalization  that  equal  areas  result  in  equal  heat  loss. 
With  this  explanation  clearly  in  mind,  we  may  proceed  to  an  analysis 
of  the  data  obtained  in  this  study,  using  the  measured  body-surface 
area  as  the  unit  of  reference. 

1  For  20  boys  and  19  girls,  nearly  all  of  them  very  young,  the  body-surfaces  were  computed  by 
the  Lissauer  formula.  The  data  given  for  these  children  do  not  therefore  represent  actual 
measurements.  (See  tables  27  and  28,  pp.  116  and  120.) 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


161 


TOTAL  CALORIES  PER  24  HOURS  REFERRED   TO  ACTUALLY  MEASURED  BODY-SURFACE 
AREA   (BOYS.) 

Employing  the  body-surface  areas  actually  measured  by  the  method 
of  Du  Bois,  we  have  plotted  in  figure  38  the  total  heat  per  24  hours 
and  the  actually  measured  body-surface  areas  for  all  of  our  boys.  As 
with  the  other  charts,  a  smoothed  curve  has  been  laid  on,  approximat- 


Cals. 
1700 

1600 
1500 
1400 
1300 
1200 
1100 
1000 
900 
800 
700 
600 
500 
400 
300 
200 
100 

0 
.2 

TOTAL  CALORIES  REFER 

RED  TO  SURFACE.                       BOYS. 

t 

0 

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sq.m..3       .4        .J 

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.7       .8       .9      1.0      1.1      1.2     1.3      1.4     1.5     1.6 

FIG.  38. — Basal  heat  production  of  boys  per  24  hours  referred  to  body-surface. 
Point  inclosed  in  square  signifies  puberty  established. 

ing  as  closely  as  possible  the  central  tendency.  In  plotting  these 
values  we  have  followed  the  scale  adopted  by  Harris  and  Benedict1 
of  considering  one-tenth  of  a  square  meter  and  100  calories  heat 
production  as  of  equal  value. 

In  contradistinction  to  the  results  obtained  on  adults,2  the  tendency 
of  the  metabolism  is  not  in  a  straight  line,  but  in  a  distinct  curve,  a 
curve  strikingly  similar  in  character  to  that  found  for  the  boys  when 

1  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  157,  diagram  26. 

2  Harris  and  Benedict,  loc.  cit. 


162  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

the  total  calories  were  referred  to  weight  in  figure  26  (page  140). 
Since  there  is  a  close  relationship  between  surface  area  and  weight, 
this  is  not  surprising,  but  it  is  important  to  note  the  scatter  of  the 
various  points  about  the  hypothetical  smoothed  curve.  If  the  heat 
production  is  more  closely  proportional  to  the  surface  area  than  it  is 
to  the  body-weight,  we  should  logically  expect  a  closer  grouping  of  the 
points  around  the  curve.  A  superficial  inspection  of  the  curves  in 
figures  38  and  26  does  not  indicate  that  the  scatter  varies  much  in 
the  two  curves.  If  anything,  it  would  appear  that  the  points  lie 
closer  to  the  curve  in  the  body-weight  chart  (fig.  26)  than  in  the 
body-surface  chart  (fig.  38).  The  question  of  absolute  scale  values 
for  ordinates  and  abscissae  enters  here,  however,  and  since  subse- 
quently both  of  these  charts  and  smoothed  curves  are  put  to  special 
use  in  an  attempt  to  predict  the  heat  production  of  the  various  children, 
further  discussion  at  this  point  is  unnecessary. 

The  smoothed  curve  indicates  a  decidedly  rapid  increase  in  metab- 
olism with  increasing  surface  area  up  to  about  0.6  square  meter. 
Thereafter,  although  there  is  an  increase  in  heat  with  larger  surface, 
it  is  somewhat  less  in  degree,  as  indicated  by  the  sketched  curve. 
Considering  the  variations  in  total  calories  for  boys  of  like  surface, 
we  find  some  striking  differences.  For  example,  with  the  surface  of 
1.3  square  meters,  one  boy  has  a  heat  production  of  1,096  calories  and 
another  of  1,401  calories,  a  difference  of  28  per  cent.  Again,  at  about 
0.80  to  0.85  square  meter,  we  have  variations  from  716  to  984  calories,  a 
difference  of  268  calories,  or  about  37  per  cent;  while  at  approximately 
0.53  square  meter  we  have  a  range  of  456  to  684  calories,  a  difference 
of  228  calories,  or  50  per  cent. 

These  percentage  differences  are  essentially  of  the  same  order  as 
that  noted  in  discussing  the  chart  showing  the  relationship  between 
weight  and  total  calories  (fig.  26,  page  140).  Indeed,  by  reference 
to  the  discussion  on  page  141,  it  will  be  seen  that  the  differences  there 
were,  if  anything,  somewhat  less.  So  far  as  this  picture  thus  far  goes, 
the  evidence  is  slightly  in  favor  of  a  greater  degree  of  regularity  in  the 
relationship  between  heat  and  weight  than  between  heat  and  body- 
surface,  even  though  we  are  now  referring  to  body-surface  accurately 
measured  and  not  approximately  computed.  A  more  rigid  test  of 
this,  however,  will  be  made  when  we  come  to  consider  in  a  subsequent 
section  the  utilization  of  the  general  smoothed  curves  in  figures  26 
and  38  as  a  basis  for  predicting  the  heat  production  of  unknown 
subjects.  What  is  of  special  physiological  significance,  however,  is 
that  the  general  picture  presented  by  the  chart  in  figure  38  indicates 
that  the  heat  production  referred  to  surface  area  is  almost  identical 
with  that  in  which  reference  is  made  to  body-weight. 

Extremely  few  children  studied  by  earlier  investigators  can  be 
compared  to  our  measurements.  They  are  confined  exclusively  to  the 


METABOLISM   AS   AFFECTED   BY   GROWTH.  163 

series  of  boys  studied  by  Du  Bois  and  his  collaborators,  whose  body- 
surface  areas  were  actually  measured.  If  any  attempt  were  made 
to  use  the  values  found  by  Magnus-Levy  and  Falk,  it  wonld  be  neces- 
sary to  calculate  the  probable  surface  area  based  only  upon  the  mea- 
surements given  by  Magnus-Levy  for  the  weight  and  height  of  the 
children  studied.  Our  analysis  of  the  anthropometric  data  obtained 
in  our  studies  shows  us  that  from  the  weight  alone  we  can  compute 
reasonably  close  values  for  practically  all  children  whose  weight  and 
sex  are  given,1  and  confirm  them  by  inspection  from  some  of  the  data 
actually  obtained  in  our  own  series.  Still,  we  do  not  wish  to  confuse 
the  comparisons  made  in  figure  38  by  introducing  computed  surface 
areas,  but  do  emphasize  the  fact  that  we  are  dealing  here  with  a  rela- 
tively recent  physical  measurement  of  children,  namely,  the  surface- 
area  by  the  Du  Bois  method.  The  values  for  Du  Bois's  1916  and  1918 
series  for  boy  scouts  have,  for  convenience,  been  included  in  figure  38, 
but  it  should  be  stated  that  these  points  were  not  laid  thereon  until 
after  our  smoothed  curve  was  prepared. 

Though  the  range  for  our  own  values  for  surfaces,  ages,  or  weights 
do  not  justify  extensive  comparison  with  the  1918  series  of  boy  scouts 
studied  by  Du  Bois,  we  have  plotted  the  latter  in  figure  38  for  purely 
comparative  purposes.  It  is  seen  that  in  almost  every  case  the 
values  found  by  Du  Bois  in  both  series  of  experiments  lie  above  our 
smoothed  curve.  While  a  few  of  these  lie  fairly  close  to  the  curve, 
most  of  them  Ire  considerably  above  it,  indicating  a  metabolism  of 
boys  with  these  measured  surfaces  noticeably  higher  than  that  found 
by  us. 

Although  it  is  probable  that  physiologists  as  a  rule  will  not  hi  the 
future  make  the  Du  Bois  measurements  a  part  of  their  regular  records, 
such  measurements  are  strongly  recommended.  At  present  the  whole 
question  as  to  the  best  index  of  physical  character  to  correlate  with 
measured  metabolism  is  still  in  abeyance.  As  pointed  out  earlier 
(see  page  53),  the  Du  Bois  measurements  have  a  specific  value  entirely 
aside  from  that  connected  with  the  computation  of  the  body-surface, 
in  that  they  give  typical  girths  and  lengths  which  are  of  importance 
for  indicating  the  several  stages  of  growth.  We  strongly  urge  all 
pediatricians  to  include  these  measurements  in  their  records  and 
in  detail.  With  the  accumulation  of  a  mass  of  data  on  this  subject, 
further  comparisons  may  be  made,  with  important  deductions  to  be 
drawn  therefrom.  Now  that  the  Du  Boises  have  given  us  an  accurate 
physical  measurement  of  surface-area,  and  as  this  measurement  more 
probably  approximates  the  true  growth-changes  than  the  measure- 
ment of  mere  weight,  the  significance  of  surface-area  measurements 
per  se  should  not  be  lost  sight  of  by  any  worker  hi  metabolism. 

1  See  tables  12  to  15,  pages  54  to  62. 


164     METABOLISM   AND   GROWTH   FROM   BIRTH   TO   PUBERTY. 

TOTAL  CALORIES  PER  24  HOURS  REFERRED  TO  ACTUALLY  MEASURED  BODY-SURFACE  AREA 

(GIRLS)  . 

The  extended  series  of  Du  Bois  measurements  were  likewise  made 
for  most  of  the  girls  in  this  study,  thus  again  permitting  the  comparison 
of  the  metabolism  with  actually  measured  surfaces.  These  data  are 
brought  together  hi  figure  39,  upon  which  we  have  laid  a  curve  showing 
the  general  trend.  There  is  clear  evidence  of  a  general  increase  in 


15OO 
1400 

1300 
1200 
1100 
1000 
900 
800 
700 
600 
500 
400 
300 
200 
100 

0 

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/ 

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. 

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/' 

.   • 

'/ 

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sq.m.3      4       .5       .6       .7       .8       .9      10      11      I 

2    li 

FIG.  39. — Basal  heat  production  of  girls  per  24  hours  referred  to  body-surface. 
Points  inclosed  in  squares  signify  puberty  established.     For  No.  239  compare  point  inclosed  in 
diamond  (prepubescence)  with  point  inclosed  in  square  at  1.272  sq.  m.  (puberty). 

metabolism  with  increasing  body-surface,  and  the  curve  is  not  unlike 
that  found  for  boys  in  figure  38.  It  also  bears  a  striking  resemblance 
to  that  found  when  the  heat  production  was  referred  to  body-weight 
with  both  boys  and  girls  (figs.  26  and  27).  The  variation  of  the 
points  above  or  below  the  central  line  is  apparently  not  unlike  that 
with  the  corresponding  curve  for  body-weight  (see  fig.  27),  and  they 
scatter  with  reasonable  regularity  about  a  fairly  straight  line.  Espe- 
cially divergent  results  are  found  at  0.52  square  meter,  and  the  two 
points  showing  a  surface  area  above  1.2  square  meters  seemingly  lie 
rather  high.  Evidently  further  observations  are  necessary  with  the 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


165 


larger  surface-areas  to  project  this  line  properly.  Hence  we  have 
purposely  ended  it  at  an  area  of  1.1  square  meters. 

The  main  conclusions  to  be  drawn  from  this  chart,  therefore,  are 
that  there  is  a  distinct  tendency  for  the  metabolism  to  be  increased 
as  the  surface-area  increases  and  after  the  lowest  areas  it  is  a  reason- 
ably straight-line  function,  so  far  as  the  general  drift  is  concerned, 
up  to  areas  of  1.1  square  meters.  Individual  points,  especially  at  the 
lower  areas,  lie  so  far  from  the  general  line  that  it  would  be  difficult  to 
conceive  of  any  physiological  regularity  that  would  suggest  an  intimate 
relationship  between  surface-area  and  the  total  calories. 

Since  none  of  the  observations  of  the  basal  metabolism  of  girls  in 
the  literature  were  accompanied  by  surface-area  measurements,  no 
points  for  earlier  values  are  placed  on  this  chart  and  no  textual  dis- 
cussion is  deemed  desirable,  as  we  are  dealing  here  with  measured 
metabolism  on  the  one  hand  and  measured  body-surface  on  the  other. 

CALORIES  PER  SQUARE  METER  OF  BODY-SURFACE  REFERRED  TO  BODY-SURFACE. 

From  the  charts  comparing  total  heat  with  measured  surface-area, 
it  is  clear  that  the  larger  areas  give  the  larger  total  heat  production 
and  that  there  is  a  tendency  above  the  lower  areas  to  a  straight-line 


Cals. 
1300 


CALORIES  PER  SO.  M.  REFERRED  TO  SURFACE. 


BOYS. 


1200 
1100 
1000 
900 
800 
700 


.2sq.m..3 


1.1       1.2      1.3     1.4     1.5 


FIG.  40. — Basal  heat  production  of  boys  per  square  meter  of  body-surface 

per  24  hours  referred  to  surface. 
Point  inclosed  in  square  signifies  puberty  established. 

relationship,  yet  the  comparison  between  the  heat  production  per 
square  meter  of  surface  writh  the  total  surface  shows  these  relation- 
ships much  more  clearly.  Accordingly  we  have  plotted  the  calories 
per  square  meter  of  body-surface  referred  to  the  surface,  in  figure  40 
for  the  boys  and  in  figure  41  for  the  girls. 

In  figure  40  it  is  perfectly  obvious  that  a  straight-line  curve  or  any- 
thing approximating  a  straight  line  will  not  correspond  with  the 
general  trend.  The  sketched  curve  shows  a  rise  in  the  calories  per 
square  meter  with  increasing  area  up  to  about  0.5  square  meter; 


166  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


thereafter  there  is  a  tendency  for  a  slow  but  reasonably  regular  fall 
with  increasing  areas.  The  scatter  of  the  points  about  this  central 
line  is  very  wide.  If  we  take  tentatively  the  line  corresponding  to 
1,000  calories  per  square  meter  as  running  through  approximately 
the  center  of  the  curve,  the  deviations  either  side  of  this  line  exceed 
10  per  cent  in  a  large  number  of  cases;  for  the  children  with  the  smaller 
body-surface  they  exceed  plus  or  minus  25  to  30  per  cent.  The 
chart  is  important,  however,  in  indicating  substantially  the  earlier 
findings  on  the  body-weight  charts,  in  that  with  small  surface-areas 

Cal8-     CALORIES  PER  SQ.  M.  REFERRED  TO  SURFACE.     GIRLS. 


1400 
1300 

1200 
11OO 
1000 
900 
800 
700 

600 
2. 

. 

- 

• 

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-s  * 

/ 

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. 

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sq.m.3      .4       .5       .6       .7       .8       .9       1.0     1.1      1.2     1. 

Fia.  41. — Basal  heat  production  of  girls  per  square  meter  of  body-surface  per  24  hours 

referred  to  surface. 

Points  inclosed  in  squares  signify  puberty  established.     For  No.  239  compare  point  inclosed  in 
diamond  (prepubescence)  with  point  inclosed  in  square  at  1.272  sq.  m.  (puberty). 

there  is  a  greater  intensity  of  metabolism  per  unit  of  surface,  not 
forgetting  the  intimate  relationship  between  surface  and  weight,  and 
that  this  does  not  depend  upon  a  causal  relationship  between  surface- 
area  and  heat-loss.  While  this  chart  is  not  readily  compared  with 
other  charts  on  the  weight  and  age  bases,  it  is  clear  that  the  scatter 
of  the  points  is  so  great  as  to  rule  out  any  conception  of  a  physiological 
law  indicating  relationship  between  the  heat  production  per  unit  of 
surface  and  the  actual  surface  as  measured  on  the  child. 

In  considering  the  calories  per  unit  of  surface-area  referred  to  total 
area  with  girls  (fig.  41),  the  characteristic  wide  scatter  of  points  noted 
with  boys  is  likewise  here  observed.  While  the  line  corresponding  to 
1,000  calories  would  roughly  fit  into  the  general  middle  of  the  curve, 
the  deviations  either  side  of  this  point  range  from  0  to  nearly  40  per 
cent  for  the  children  of  smaller  body-surface  but  from  0.7  to  1.1  sq.  m., 
the  points  group  themselves  somewhat  better  about  the  central  line 
than  they  do  with  boys.  The  specific  high  metabolism  with  the  smaller 
children  and  the  absence  of  any  regularity  in  the  chart  as  a  whole  which 
would  suggest  a  physiological  law  should  be  emphasized. 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


'167 


We  believe  that  this  is  the  first  time  that  actually  measured  surfaces 
have  been  so  extensively  applied  in  comparisons  with  the  simul- 
taneously measured  total  calories.  So  far  as  the  total  calories  are 
concerned,  the  general  trend  with  both  boys  and  girls  is  not  unlike 
that  for  the  total  heat  referred  to  weight.  So  far  as  the  calories  per 
square  meter  referred  to  area  are  concerned,  the  deviations  from  the 
central  line  are  too  great  to  permit  of  any  theorizing  as  to  the  existence 
of  a  strict  physiological  relationship  between  heat  production  and 
surface  area. 

COMPARISON  OF  CALORIC  OUTPUT  PER  SQUARE  METER  OF  BODY-SURFACE  WITH 
TOTAL  BODY- WEIGHT. 

In  the  discussion  of  the  charts  dealing  with  body-surface  thus  far, 
we  have  seen  that  with  increasing  body-surface  there  is  an  increased 
total  heat  production,  but  when  the  calories  per  square  meter  of  body- 
surface  are  referred  to  the  surface,  the  general  trend  shows  an  increase 
in  the  metabolism  to  an  area  of  0.5  sq.  m.,  and  thereafter  a  definite 


CALORIES  PER  SO.  M.  REFERRED  TO  WEIGHT. 


BOYS. 


1250 
1200 
1150 
1100 
1050 
1000 
950 
900 
850 
800 
750 
700 
650 

600 

2 

• 

. 

. 

/ 

/^~ 

~\. 

^s, 

• 

/ 

\ 

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. 

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. 

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ZSSr 

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/' 

I 

I 

1 

1 

• 

' 

kgs.4 

3       10      12       14      16      18      20      22      24      26      28     30      32      34      36      38      40     4 

FIG.  42. — Basal  heat  production  of  boys  per  square  meter  of  body-surface  per  24  hours 

referred  to  body-weight. 
Point  inclosed  in  square  signifies  puberty  established. 

decrease.  These  results  throw  absolutely  no  light  upon  the  possi- 
bility of  a  relationship  between  area  and  heat  production,  for  the 
surface  may  be  simply  another  approximate  expression  of  increasing 
body-mass,  and  particularly  the  mass  of  organic  protoplasmic  tissue 


168  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

participating  in  heat  production.  Accordingly  a  comparison  of  the 
heat  production  per  square  meter  of  body-surface  with  children  of 
different  weights  has  a  special  interest.  This  comparison  is  made  for 
the  boys  in  figure  42. 

The  wide  scatter  of  points  on  this  chart  makes  the  drawing  of  any 
smoothed  curve  very  problematical.  About  the  only  clear  feature  of 
the  plot  is  that  a  straight-line  curve  will  not  represent  the  general 
trend,  for  there  is  decided  evidence  of  a  gradual  increase  in  the  heat 
production  per  square  meter  of  body-surface  up  to  about  12  kg.  in 
weight,  with  a  decrease  thereafter.  This  increase,  of  course,  has 
special  interest  for  comparison  with  the  rise  in  the  intensity  of  meta- 
bolism in  the  first  part  of  the  curves  shown  on  several  of  our  earlier 
charts.  This  increase  thus  seems  to  be  clearly  established,  whatever 
basis  of  comparison  is  employed. 

It  is  commonly  believed  that  the  calories  per  square  meter  are 
constant  for  all  sizes  and  weights  of  individuals.  The  surface  areas 
here  shown  are  not  computed  or  estimated,  but  are  carefully  measured ; 
yet  on  this  chart  we  find  variations  in  the  calories  per  square  meter 
ranging  from  647  calories  at  a  weight  slightly  under  4  kg.  to  a  maxi- 
mum of  1,278  calories  at  a  weight  of  about  12  kg.  This  great  diversity 
occurs  with  the  lower  weights,  but  even  after  12  kg.,  taking  for  example 
a  point  at  approximately  28  to  30  kg.,  we  have  ranges  from  886  to 
1,205  calories. 

The  sketched  curve  is  not  unlike  that  shown  when  the  calories  per 
square  meter  are  compared  with  the  actually  measured  surface-area 
(fig.  40),  but  it  is  impossible  to  consider  such  a  wide  scatter  of  obser- 
vations as  indicating  more  than  a  general  trend.  While,  as  would  be 
expected,  a  considerable  number  of  points  lie  within  ±10  per  cent, 
especially  at  the  higher  weight  values,  the  large  number  of  points 
lying  outside  these  wide  limits  certainly  does  not  justify  the  effort 
to  stress  this  relationship  as  evidence  of  a  physiological  law. 

The  calories  per  24  hours  per  square  meter  of  body-surface  referred 
to  weight,  as  plotted  for  the  girls  in  figure  43,  show  such  a  wide  diversity 
in  the  distribution  of  the  individual  points  that  only  a  complicated 
form  of  curve,  which  has  obviously  not  been  mathematically  deter- 
mined, will  serve  to  indicate  the  general  trend.  Characteristics  of 
this  sketched  curve  are  the  rapid  increase  in  the  values  up  to  10  kg. 
in  weight,  and  a  tendency  for  the  values  to  decrease  thereafter.  Con- 
trary to  the  results  of  the  observations  on  boys,  there  is  with  girls  a 
clear  tendency  in  the  relatively  few  observations  we  have  to  indicate  a 
flattening-out  of  the  curve  after  22  kg.  Still,  extreme  caution  is 
necessary  in  considering  any  data  above  30  kg.  as  of  real  significance 
in  indicating  the  general  trend,  since  we  have  only  three  points  beyond 
this  weight.  The  two  extremely  high  values  between  36  and  40  kg. 
are  the  identical  observations  which  showed  abnormally  high  values 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


169 


on  the  body-surface  chart  in  figure  39.  Further  evidence  at  these 
weights  is  absolutely  necessary  for  intelligent  discussion.  The  accumu- 
lation of  such  data  is  now  in  progress  at  the  Nutrition  Laboratory. 


CALORIES  PER  SQ.  M.  REFERRED  TO  WEIGHT. 


1300 

. 

1250 

1?00 

115O 

* 

• 

1100 

.^ 

1050 

'    / 

/ 

^ 

\ 

1000 

/ 

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900 

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650 

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5      1 

i      2 

0     2 

2     2 

4      2 

6     2 

8     3 

0     3 

2     3 

4      3 

6     3 

8      4 

FIG.  43. — Basal  heat  production  of  girls  per  square  meter  of  body-surface  per  24  hours 

referred  to  body-weight. 

Points  inclosed  in  squares  signify  puberty  established.     For  No.  239  compare  point  inclosed  in 
diamond  (prepubescence)  with  point  inclosed  in  square  at  39.2  kg.  (puberty). 

Although  the  tendency  is  for  the  highest  metabolism  per  square 
meter  of  body-surface  to  be  noted  at  about  10  kg.,  some  of  the  lowest 
values  found  in  the  entire  series  are  also  obtained  about  this  time. 
A  large  personal  element  in  basal  metabolism  is  therefore  apparent, 
certainly  with  the  younger  children.  The  general  form  of  the  curve 
is  somewhat  different  from  that  on  the  same  basis  shown  for  the  boys, 
but  this  is  not  the  place  for  a  special  discussion  of  sexual  differentiation. 

COMPARISON  OF  HEAT  PRODUCTION  PER  SQUARE  METER   (MEASURED),   REFERRED  TO 
BODY- WEIGHT,  WITH  EARLIER  DATA  (COMPUTED). 

As  brought  out  in  preceding  sections,  certain  difficulties  occur  in 
comparing  the  results  of  our  study,  in  which  the  basal  metabolism 
was  directly  determined  and  the  surface-area  actually  measured,  with 
those  of  earlier  investigators,  who,  aside  from  Du  Bois,  were  unable  to 
measure  the  body-surface.  Since,  however,  data  were  obtained  in  the 


170  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

earlier  investigations  for  the  total  metabolism  and  the  body-weight, 
and  occasionally  for  height  and  age,  we  may  compute  the  surface 
areas  for  the  children  studied,  probably  with  considerable  exactness. 

In  computing  the  body-surfaces  of  children  whose  metabolism  is 
given  in  the  earlier  literature,  we  have  been  guided  in  large  part 
(1)  by  the  clearly  established  legality  of  the  Lissauer  formula  for  chil- 
dren up  to  10  kg.  in  weight;  (2)  by  the  reasonably  satisfactory  agree- 
ment of  the  Du  Bois  height-weight  chart  down  to  20  kg.  with  body- 
surfaces  actually  measured.  For  the  children  studied  by  Murlin  and 
Hoobler,  the  body-surface  was  computed  by  means  of  the  Lissauer 
surface  formula.  For  the  majority  of  those  studied  by  Magnus-Levy 
and  Falk,  the  surface  areas  were  derived  from  the  height-weight  chart 
of  Du  Bois.  Since  no  heights  were  given  for  Scharling's  children,  the 
two  boys  of  Sonde"n  and  Tigerstedt,  and  a  few  of  Magnus-Levy  and 
Falk's  children,  the  surface  areas  were  computed  from  the  body-weights 
by  means  of  the  formula  K  ^5*  and  our  new  values  for  the  factor  K. 
(See  tables  14  and  15,  pages  61  and  62.) 

The  use  of  these  computed  surface  areas  is  permissible  in  computing 
the  calories  per  square  meter  of  body-surface;  but  it  hardly  seems  that 
such  a  computed  area  can  be  used  in  a  comparison  of  the  calories 
per  square  meter  of  body-surface  and  the  body-surface  itself,  and 
this  has  not  been  attempted.  In  referring  the  calories  per  square 
meter  to  weight  and  to  age,  the  units  of  measurement  for  comparison 
are  perfectly  definite  and  hence  proper  to  use. 

To  avoid  any  misunderstanding,  we  call  attention  again  to  the 
fact  that  for  some  of  the  very  young  children  (20  boys  and  19  girls) 
in  our  own  series  of  observations,  the  body-surfaces  were  not  measured, 
but  were  likewise  computed.1  For  these  children  the  Lissauer  formula 
was  used,  as  it  was  not  possible  to  employ  the  height-weight  chart, 
since  the  body-weight  was  less  than  20  kg.,  which  is  the  lower  limit 
of  this  chart.  As  our  own  results  show  that  the  Lissauer  formula 
agrees  remarkably  well  with  the  measured  surfaces  for  other  children 
weighing  less  than  10  kg.,  we  feel  justified  in  including  these  in  our 
tables  with  the  actually  measured  surfaces. 

If  we  disregard  the  age  of  the  child  measured  by  Sawyer,  Stone,  and 
Du  Bois,2  and  consider  only  weight,  it  seems  quite  reasonable  to  argue 
that  since  the  Du  Bois  measurements  applied  to  a  child  weighing  a 
little  over  6  kg.  and  the  Lissauer  formula  and  the  linear  measure- 
ments agree  up  to  10  kg.,  we  can  logically  employ  the  Du  Bois  linear 
formula  in  measuring  the  body-surface  of  children  weighing  somewhat 
less  than  6.3  kg.  Du  Bois  specifically  questions  the  use  of  the  linear 
formula  for  body-surface  calculations  for  children  under  2  years  of  age. 
It  would  appear,  however,  that  the  agreement  between  the  Lissauer 

1  See  tables  27  and  28,  pp.  116  and  120. 

2  Sawyer,  Stone,  and  Du  Bois,  Arch.  Intern.  Med.,  1916,  17,  p.  855. 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


171 


formula  and  the  Du  Bois  surface  formula  is  not  a  purely  accidental 
one,  but  represents  in  all  probability  a  reasonably  close  physiological 
relationship.  Accordingly,  while  we  must  recognize  that  the  Du  Bois 
linear  formula  may  not,  according  to  its  authors,  be  used  at  present 
for  children  under  2  years  of  age,  we  have  frankly  disregarded  this  and 
have  employed  it  for  these  younger  children  in  computing  the  body- 
surfaces  from  the  actual  measurements.  Until  it  has  been  disproved 
that  the  linear  formula  does  not  apply  for  children  so  young  as  this, 
we  believe  it  is  justifiable  to  use.  it  in  this  way.  If  body-surface  still 
continues  to  attract  the  attention  of  physiologists  as  much  as  it  has 
in  the  past  decades,  a  complete  verification  of  the  linear  formula  for 
children  under  2  years  of  age  may  naturally  be  expected  inside  of  a 
few  years. 


CALORIES  PER  SO-  M.  REFERRED  TO  WEIGHT. 


1350 
1300 
1250 
1200 
1150 
11  00 
1050 
1000 
950 
900 
850 
800 
750 
700 
650 

600 
2 

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o-DU  BOIS  (1916) 
o-DU  BOIS  (1918) 

kgs.4        < 

FIG.  44. — Basal  heat  production  of  boys  per  square  meter  of  body-surface  per  24  hours 
referred  to  body-weight  (earlier  investigators). 

In  the  comparison  of  our  metabolism  data  with  earlier  studies,  in 
which  special  attention  is  called  to  the  total  calories  per  square  meter 
per  24  hours  referred  to  body-weight,  it  is  necessary  to  bear  strictly 
in  mind  that  the  surface-areas  of  the  children  studied  by  the  earlier 
investigators  were  all  computed,  except  those  for  the  Du  Bois  boy 
scouts.  We  have  charted  the  values  for  boys  on  the  usual  scale  in 
figure  44.  The  sketched  curve,  which  shows  the  general  tendency 


172  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


found  in  our  own  results,  has  also  been  laid  on  the  chart,  although 
here  again  it  must  be  emphasized  that  this  curve  was  drawn  with 
great  difficulty  and  simply  shows  the  general  trend  in  a  diagram, 
with  very  wide  dispersion  of  the  various  points. 

While  comparison  with  figure  42  shows  that  few  of  these  points  lie 
outside  of  the  field  of  our  observations,  yet  we  should  note  that,  with 
the  exception  of  one  boy  weighing  about  6  kg.,  the  points  for  the 
children  earlier  studied  lie  above  our  sketched  curve.  Furthermore, 
if  a  smoothed  curve  were  laid  through  the  earlier  observations,  it 
would  have  approximately  the  same  general  trend  as  our  own  curve, 
although  at  a  higher  level. 

While  our  own  data  do  not  warrant  the  extension  of  our  smoothed 
curve  beyond  42  kg.,  the  data  for  certain  heavier  boys  should  here  be 
recorded.  In  the  1918  series  of  Du  Bois,  the  values  for  four  boys,  all 
weighing  about  49  kg.,  are  reported  and  are  given  in  table  30.  With 
all  four  boys  the  surfaces  were  actually  measured. 


TABLE  30.  —  Values  outside 
weight  range  in  figure  44  COt* 
Bois) . 


TABLE  31. — Values  outside  heat  range  in  figure  44 
(Magnus-Levy  and  Falk) . 


Cals.  per 

Kilos. 

sq.  m.  per 

24  hrs. 

49.1 

1,054 

49.1 

1,037 

49.3 

1,039 

48.6 

938 

Method. 

Kilos. 

Cals.  per 
sq.  m.  per 
24  hrs. 

Height-weight  chart  

20.8 

1,459 

K^lw1  

11.5 

1,448 

***  

14.5 

1,468 

Magnus-Levy  and  Falk  report  the  heat  production  of  three  boys, 
each  with  such  a  high  value  that  it  would  be  necessary  to  extend 
our  chart  beyond  permissible  limits  to  include  them,  although  they 
weighed  less  than  21  kg.  Table  31  shows  the  data  for  these  three  boys. 

It  is  clear  that  the  points  for  6  of  the  7  boys  would  lie  very  con- 
siderably above  our  line  if  projection  beyond  the  42-kg.  level  were 
permissible.  Since  we  believe  that  the  projection  would  in  all  prob- 
ability fall  somewhat  lower  rather  than  continue  on  a  level,  all  of 
the  7  boys  would  be  above  the  projected  line,  although  the  value  for 
the  boy  weighing  48.6  kg.  studied  by  Du  Bois  would  fall  practically 
on  the  line. 

With  girls  the  number  of  earlier  observations  is  extremely  few, 
hardly  justifying  special  chart  treatment.  The  values  have  been 
plotted,  but  are  not  reproduced  here.  All  of  the  values  are  con- 
siderably above  our  smoothed  curve.  The  earlier  data  for  girls 
are  altogether  too  sparse  to  warrant  even  an  attempt  to  lay  on  a 
smoothed  curve,  so  no  comparisons  with  our  general  trend  are 
possible. 


METABOLISM   AS   AFFECTED   BY   GROWTH.  173 

Thus,  with  girls,  as  with  boys,  practically  all  of  the  earlier  work 
shows  a  metabolism  so  much  higher  than  that  found  by  us  as  to  lead 
us  to  suspect  that  strict  maintenance  of  muscular  repose  was  not 
insisted  upon  in  these  earlier  observations.  Our  own  results  obvi- 
ously more  nearly  approach  basal,  though  still  not  uncomplicated 
by  a  possible  effect  of  previously  eaten  food. 

AGE  RELATIONS  IN  THE  HEAT  PRODUCTION  PER  SQUARE  METER  OF  BODY-SURFACE. 

Thus  far  the  consideration  of  the  heat  loss  per  square  meter  of  body- 
surface  for  our  subjects  has  been  confined  to  the  two  bases,  weight  and 
measured  body-surface.  In  view  of  the  small  and  clearly  established 
age  relationship  in  the  metabolism  of  adults,  it  is  important  to  note 
whether  age  has  a  special  effect  upon  the  metabolism  of  rapidly  growing 
children.  As  previously  pointed  out,  the  differentiating  of  the  age 
effect  is  difficult,  owing  to  the  fact  that  age  changes  are  concurrent 
with  weight,  stature,  and  surface  changes.  Still,  for  purposes  of 
special  discussion  in  subsequent  chapters,  it  is  advisable  to  consider 
the  heat  per  square  meter  referred  to  age  exactly  as  we  have  studied 
the  total  calories  and  the  calories  per  kilogram  of  body-weight  referred 
to  age.  This  is  particularly  true  when  it  is  recalled  that,  beginning 
with  the  days  of  Andral  and  Gavarret,  special  emphasis  has  been 
placed  upon  the  influence  upon  metabolism  of  approaching  puberty; 
hence  in  our  curves  it  is  desirable  to  note  the  ages  of  the  various 
individuals  and  to  find  the  general  trend  of  metabolism  at  these  ages, 
independent  of  weight  or  surface,  save  as  the  surface  area  is  partly 
compensated  by  computing  the  heat  per  square  meter  exactly  as  weight 
has  been  partly  compensated  in  previous  comparisons  by  computing 
the  heat  per  kilogram  of  body-weight. 

Figure  45  gives  the  values  for  boys  for  heat  per  square  meter  of 
body-surface  referred  to  age.  Recalling  that  age  changes  are  in  the 
main  concurrent  with  weight  and  surface  changes,  it  can  be  seen  that 
the  general  trend  of  this  curve  is  somewhat  similar  to  that  for  the  cal- 
ories per  square  meter  when  referred  to  weight  (fig.  42)  and  when 
referred  to  body-surface  (fig.  40),  exhibiting  an  increase  during  the 
early  years  up  to  an  age  of  about  2  years,  with  a  tendency  towards  a 
straight-line  decrease  thereafter.  The  scatter  of  individual  points 
makes  it  difficult  to  lay  on  a  smoothed  curve.  We  do  not  defend  this 
use  of  a  straight-line  curve  and  can  only  take  refuge  in  our  oft-repeated 
statement  that  the  line  must  be  understood  to  indicate  only  a  trend 
and  may  not  be  referred  to  with  any  mathematical  exactness. 

As  in  previous  charts,  one  of  the  boys  is  marked  as  showing  un- 
mistakable signs  of  puberty,  this  point  lying  above  our  smoothed 
curve.  Attention  will  be  again  called  to  this  fact  in  subsequent 
discussion  of  the  influence  of  the  prepubertal  stage  upon  metabolism. 


174  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


The  chief  importance  of  the  curve  in  figure  45  is  to  show  the  pro- 
nounced metabolism  of  early  youth  up  to  1  or  2  years.  As  we  have 
already  stated,  there  can  be  no  great  preponderance  in  the  proportion 
of  active  protoplasmic  tissue  in  a  child  1  or  2  years  of  age.  In  all 
probability  we  have  here  a  specifically  high  metabolism  at  this  age, 
which  is  certainly  worthy  of  further  investigation,  with,  if  possible, 
a  minimizing  or  elimination  of  the  disturbing  factor  of  stimulus 
from  food  (see  page  30). 

Cals.  CALORIES  PER  SQ.  M.  REFERRED  TO  AGE. 


67J 


12       13       14       15      16 

FIG.  45. — Basal  heat  production  of  boys  per  square  meter  of  body-surface  per 

24  hours  referred  to  age. 
Point  inclosed  in  square  signifies  puberty  established. 

For  the  studies  on  boys  made  by  earlier  investigators,  a  plot  is 
made  in  figure  46  and  our  smoothed  curve  included  in  the  chart.  The 
usual  experience  is  here  repeated,  namely,  that  the  earlier  values, 
with  but  one  exception,  lie  above  the  smoothed  curve;  in  most  in- 
stances, the  points  are  very  much  above  the  line.  Especially  worthy 
of  note  are  the  high  values  recorded  by  Du  Bois  between  the  ages  of 
12  and  14  years.  These  have  brought  once  more  into  active  discussion 
the  influence  of  the  prepubertal  stage  upon  basal  metabolism. 

Our  observations  on  girls  are  all  plotted  in  figure  47,  upon  which 
is  laid  a  somewhat  complicated  smoothed  curve,  this  being  the  result 
of  an  attempt  to  represent  the  general  trend  in  spite  of  the  great 
irregularity  and  wide  dispersion  of  individual  points.  The  most  clearly 
established  feature  of  the  curve  is  the  prevalence  of  low  values  at  the 
early  ages,  rapidly  ascending  until  about  1  or  2  years,  with  a  tendency 
towards  a  subsequent  decrease.  With  two  of  the  girls,  puberty  was 
definitely  established  and  with  one  other  it  was  beginning.  Of  the 


METABOLISM   AS   AFFECTED   BY   GROWTH. 


175 


two  former,  one  point  lies  below  the  curve  and  the  other  considerably 
above  it.  The  point  for  the  third  girl  (12  years  and  2  months)  lies 
slightly  below  the  smoothed  curve.  With  one  of  these  girls,  measure- 
ments were  made  prior  to  and  subsequent  to  puberty.  At  the  age  of 


CALORIES  PER  SQ.  M.  REFERRED  TO  AGE. 


rf-SCHARLING 

.SONDEN  AND  TIGERSTEDT 
-MAGNUS-LEVY  AND  FALK 


^.-MURLIN  AND  HOOBLER 
o-DU  BOIS(1916) 
D-DU  BOIS0918) 


FIG.  46. — Basal  heat  production  of  boys  per  square  meter  of  body-surface  per  24  hours 
referred  to  age  (earlier  investigators). 


CALORIES  PER  SO-  M.  REFERRED  TO  AGE. 


GIRLS. 


FIG.  47. — Basal  heat  production  of  girls  per  square  meter  of  body-surface  per  24  hours 

referred  to  age. 

Points  inclosed  in  squares  signify  puberty  established.     For  No.  239  compare  point  inclosed  in 
diamond  (prepubescence)  with  point  inclosed  in  square  at  12  years  1  month  (puberty). 


176  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

11  years,  prior  to  puberty,  the  heat  per  square  meter  was  909  calories. 
Somewhat  over  a  year  later,  when  the  child  was  12  years  and  1  month 
old,  the  heat  per  square  meter  had  increased  to  1,179  calories. 
This  will  likewise  receive  special  consideration  subsequently. 

Bearing  in  mind  that  age,  weight,  and  surface  area  changes  are  so 
closely  interwoven,  it  is  impossible  in  any  of  these  age  charts  to 
emphasize  specifically  an  age  influence  per  se,  other  than  to  draw 
attention  to  the  high  point  at  the  age  of  1  or  2  years  which  seems 
unquestionably  to  be  a  specific  age  influence. 

The  extremely  few  girl  subjects  in  the  earlier  literature  make  a 
comparison  with  our  work  impracticable.  Such  few  observations  as 
are  on  record  that  can  be  taken  as  approximating  basal  (chiefly  those 
of  Magnus-Levy  and  Falk)  would  all  lie  considerably  above  our  general 
smoothed  curve.  Special  chart  representation  for  these  scattered 
observations  hardly  seems  necessary. 

INFLUENCE  OF  SEX  AND  SEXUAL  CHANGE  ON 
METABOLISM. 

The  wide  differences  in  activity  and  dietetic  habits  of  boys  and 
girls,  commonly  observed  in  every  household,  early  led  to  a  belief  in  a 
striking  difference  between  the  metabolism  of  children  of  the  two 
sexes.  Unfortunately,  many  of  the  earlier  comparisons  disregarded 
body-weight  and  considered  age  only.  While  age-changes  with 
both  boys  and  girls  are  closely  followed  by  weight-changes,  for  a 
strict  comparison  it  is  obvious  that  one  may  not  compare  a  12-year- 
old  boy  weighing  38  or  40  kg.  with  a  12-year-old  girl  weighing  30  kg. 

Even  the  early  experiments  of  Andral  and  Gavarret1  are  used  by 
the  authors  as  the  basis  for  considerable  discussion  of  the  differences 
between  boys  and  girls.  As  the  authors  did  not  report  the  body- 
weights  of  the  children,  we  can  not  recompute  the  data  on  the  better 
basis  of  energy  per  kilogram  of  body-weight.  They  conclude  that 
with  boys  and  men  there  is  a  steady  increase  in  the  carbon-dioxide 
production  from  8  to  30  years,  and  that  between  these  ages  the  carbon- 
dioxide  production  is  greater  in  amount  than  that  of  girls  and  women 
of  similar  ages.  Furthermore,  they  believe  that  the  sexual  difference 
is  most  pronounced  in  the  adult  period  (16  to  40  years),  the  exhalation 
of  carbon  dioxide  by  man  during  this  period  being  about  twice  as 
much  as  that  of  woman.  The  work  of  Andral  and  Gavarret  is  admir- 
ably presented  by  Sonden  and  Tigerstedt2  in  connection  with  the 
discussion  of  their  own  researches.  As  the  results  of  Andral  and 
Gavarret  or  of  Sonde"n  and  Tigerstedt  may  not  be  looked  upon  as 
basal  in  character,  the  comparison  is  probably  justifiable,  since  in  all 

1  Andral  and  Gavarret,  Ann.  d.  Chim.  et  d.  Phys.,  1843,  s6r.  3,  8,  p.  129. 

2  Sonden  and  Tigerstedt,  Skand.  Arch.  f.  Physiol.,  1895,  6,  pp.  54  and  56. 


INFLUENCE   OF   SEX   ON   METABOLISM.  177 

cases  the  subjects  were  fairly  quiet,  although  modern  conditions  for 
basal  measurements  were  not  obtained. 

That  the  question  of  body-weight  was  seriously  considered  by 
Andral  and  Gavarret  is  shown  by  a  portion  of  their  discussion,  but 
they  discard  this  method  of  comparison  as  irrational,  maintaining 
that  while  a  woman  25  years  old  weighs  much  more  than  a  child  10 
to  14  years  old,  she  produces  no  more  carbon  dioxide.  They  further 
contend  that  at  the  menopause  the  body-weight  of  women  does  not 
necessarily  increase,  and  they  have  shown  that  the  exhaled  carbon 
dioxide  at  that  time  continually  increases.  It  is  a  matter  of  regret  to 
modern  writers  that,  although  the  body-weights  of  the  subjects  were 
known  to  these  investigators,  they  did  not  publish  them. 

Special  emphasis  was  laid  by  Andral  and  Gavarret  upon  the  influence 
of  puberty  on  metabolism.  They  maintain  that  with  boys  the  carbon 
dioxide  exhaled  increases  suddenly  to  a  large  amount  at  the  time  of 
puberty,  while  with  girls,  on  the  contrary,  the  carbon  dioxide  excretion 
suddenly  ceases  to  increase  at  this  period  and  remains  nearly  stationary 
until  the  menopause.  It  then  suddenly  increases  in  a  very  remarkable 
manner,  and  finally,  as  with  man,  decreases  in  proportion  to  the 
approach  to  extreme  old  age. 

Speck1  studied  only  three  children  within  the  age-range  observed 
by  us  (a  girl  of  10  years,  a  girl  of  13  years,  and  a  boy  of  13  years), 
and  his  conclusions  were  largely  based  upon  experiments  made  with 
older  individuals;  hence  they  have  little  immediate  significance  in 
our  discussion. 

Most  of  the  discussion  as  to  the  difference  between  the  sexes  in  the 
classic  paper  of  Magnus-Levy  and  Falk2  pertains  to  the  ages  beyond 
those  of  childhood.  According  to  their  results,  the  total  metabolism 
of  boys  during  the  years  of  puberty  did  not  exceed  that  of  adult  normal 
men.  With  some  of  the  boys  the  metabolism  was  less  and  with  some 
approximately  the  same  as  that  found  with  adult  men.  They  men- 
tion particularly  one  boy,  accustomed  to  metabolism  experiments, 
who  was  studied  when  he  was  16  years  old  and  weighed  57.5  kg.,  and 
again  6  years  later,  when  he  was  10  kg.  heavier.  During  the  period 
of  establishment  of  puberty  the  oxygen  consumption  was  235.6  c.  c. 
per  minute  and  the  carbon-dioxide  production  192.2  c.  c.  When 
puberty  had  been  fully  established,  the  oxygen  consumption  was 
231.3  c.  c.  and  the  carbon-dioxide  production  200.2  c.  c.  per  minute. 
In  other  words,  approximately  the  same  values  were  found  at  both 
times.  In  the  later  stages  of  the  period  of  pubertal  change,  therefore, 
the  total  metabolism  corresponded  to  that  found  after  puberty  had 
been  fully  established.  Since  there  was  an  increase  in  weight,  the 
metabolism  per  kilogram  of  body-weight  obviously  decreased,  i.  e., 

1  Speck,  Physiologie  des  menschlichen  Athmens,  Leipsic,  1892,  p.  217. 

2  Magnus-Levy  and  Falk,  Archiv  f.  Anat.  u.  Physiol.,  1899,  Suppbd.,  p.  314. 


178  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

the  oxygen  consumption  from  4.10  c.  c.  to  3.43  c.  c.  per  minute  per 
kilogram. 

Their  conclusions  are  as  follows:  The  gaseous  exchange  of  children 
per  unit  of  weight  is  greater  than  with  adults,  being  larger  the  younger 
and  lighter  the  child;  this  does  not  apply  to  the  first  year  of  life. 
Per  unit  of  body-surface  (Meeh) ,  the  metabolism  of  children  is  much 
greater  than  that  of  adults,  but  during  the  first  year  of  life  it  is  prob- 
ably somewhat  lower  than  during  later  child  life. 

The  metabolism  of  females  is  not  actually  less  than  that  of  males; 
certainly  with  adults  there  is  no  difference.  In  this  respect  they  do 
not  agree  with  Sonden  and  Tigerstedt,  who  believe  that  the  meta- 
bolism of  women  is  less  than  that  of  men. 

With  the  younger  children  the  gaseous  exchange  per  kilogram  of 
body-weight  for  girls  is  somewhat  less  than  with  boys;  with  larger 
children  the  gaseous  exchange  is  about  the  same  with  boys  and  girls. 
In  general,  Magnus-Levy  and  Falk  conclude  that  the  metabolism  of 
women  in  middle  life  is  approximately  the  same  per  kilogram  of  body- 
weight  as  that  of  adult  men  of  the  same  age  and  weight;  with  children 
and  elderly  people,  the  metabolism  of  females  is  slightly  less  than  that 
of  males  (about  5  to  10  per  cent). 

Finally,  we  should  refer  to  the  conclusions  of  Sonde"n  and  Tigerstedt,1 
although  these  were  not  founded  upon  basal  metabolism  measure- 
ments. These  investigators  maintain  that  in  general  the  carbon- 
dioxide  production  of  boys,  on  the  basis  of  both  weight  and  surface, 
is  considerably  greater  than  that  of  girls  of  the  same  age  and  body- 
weight,  and  that  the  carbon  dioxide  production  of  girls,  both  per  kilo- 
gram of  body-weight  and  per  square  meter  of  body-surface  as  computed 
by  the  Meeh  formula,  is  to  the  boys  as  100  is  to  141.  This  finding, 
as  Sonde"n  and  Tigerstedt  point  out,  was  earlier  suggested  by  Scharling2 
and  Speck,3  as  well  as  Andral  and  Gavarret,4  although  the  experiments 
of  Scharling  and  Speck  were  so  few  as  to  make  their  deductions  little 
more  than  speculation. 

In  considering  the  several  charts  and  diagrams  for  the  measurements 
made  upon  our  boys  and  girls,  we  have  occasionally  hinted  at  small 
but  obvious  sexual  differences  in  the  general  form  of  the  curves. 
Still,  from  a  casual  inspection  of  the  individual  curves,  it  would  be 
almost  impossible  to  assert  the  presence  of  a  pronounced  sexual 
differentiation.  For  the  special  purpose  of  noting  sex  differences,  if 
they  exist,  comparison  should  be  made  upon  the  same  chart.  In 
figure  48  the  total  calories  are  referred  to  body-weight  for  both  boys 
and  girls,  the  two  curves  being  taken  directly  from  figures  26  and  27, 

1  Sonden  and  Tigerstedt,  Skand.  Archiv  f.  Physiol.,  1895,  6,  p.  95. 

» Scharling,  Ann.  d.  Chem.  u.  Pharm.,  1843,  45,  p.  214;   reprinted  in  detail  in  Ann.  d.  Chim.  et 

d.  Phys.,  1843,  ser.  3,  8,  p.  478. 

8  Speck,  Physiologic  des  menschlichen  Athmens,  Leipsic,  1892. 
4  Andral  and  Gavarret,  Ann.  d.  Chim.  et  d.  Phys.,  1843,  ser.  3,  8,  p.  129. 


INFLUENCE   OF   SEX   ON   METABOLISM. 


179 


respectively,  and  here  superimposed.  In  this  comparison  of  total 
calories  to  weight,  we  find  that  the  absence  of  a  real  sexual  difference 
shown  with  new-born  infants1  persists  until  about  the  weight  of  11  kg., 
and  that  subsequently  there  is  a  tendency  for  the  boys  to  have  a 
somewhat  higher  metabolism  than  girls  of  the  same  weight,  the  line 
for  boys  being  perceptibly  above  that  for  girls. 


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FIG.  48. — Comparison  of  basal  heat  production  of  children  and  adults  per  24  hours 
referred  to  body-weight. 

Attention  should  here  be  called  to  the  fact  that  in  the  preliminary 
presentation  of  this  material,2  a  somewhat  different  relationship 
between  the  curves  for  boys  and  girls  was  noted  in  that  the  curve  for 
girls  rose  above  that  for  boys  at  the  weight  of  35  kg.  Subsequent 
revision  and  elision  has  justified  the  caution  pronounced  at  that  time 
to  the  effect  that  the  number  of  individuals  measured  at  the  higher 
weights  were,  with  both  sexes,  too  few  to  justify  sweeping  conclusions. 
As  here  shown  in  the  latest  and  more  complete  analysis  of  our  material, 
we  have  clear  evidence  of  a  sexual  differentiation  in  basal  metabolism 
exhibited  above  11  kg.,  in  which  the  boys  show  persistently  a  somewhat 
higher  metabolism  than  girls  of  the  same  weight. 

Since  a  comparison  of  the  metabolism  of  youth  and  adults  is  of 
general  interest,  the  trends  of  the  metabolism  on  the  basis  of  total 
calories  referred  to  weight  are  also  shown  in  figure  48  for  men  and 
women.  These  curves  will  be  given  special  discussion  later. 

A  comparison  may  also  be  made  of  the  two  curves  for  boys  and 
girls  in  figures  38  and  39,  in  which  the  total  heat  was  referred  to  actual 
measurements  of  the  body-surface  by  the  Du  Bois  method.  This 

1  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  233,  1915;  Harris  and  Benedict,  Carnegie 

Inst.  Wash.  Pub.  No.  279,  1919,  p.  219. 

2  Benedict,  Boston  Med.  and  Surg.  Journ.,  1919,  181,  p.  107. 


180  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


comparison  has  been  made  in  figure  49.  As  has  been  pointed  out,  the 
general  trend  of  the  two  curves  is  alike  and  the  two  sexes  remain 
at  essentially  the  same  metabolism  until  the  area  is  0.48  sq.  m.  From 
this  point  the  line  for  the  boys  rises  above  that  for  the  girls,  and  there 
is  no  evidence  of  a  tendency  for  the  two  lines  to  cross  later.  Figures 
48  and  49  thus  give  clear  evidence  of  a  sexual  differentiation  between 
boys  and  girls,  with  the  boys  on  the  whole  showing  a  higher  meta- 
bolism after  the  body-weight  and  body-surface  have  reached  11  kg. 
and  0.48  sq.  m.,  respectively. 


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FIG.  49. — Comparison  of  basal  heat  production  of  children  and 
adults  per  24  hours  referred  to  body-surface. 

The  comparison  of  the  total  calories  to  measured  surface  is,  however, 
a  somewhat  novel  procedure,  and  physiologists  are  more  accustomed 
to  comparisons  of  the  calories  per  kilogram  of  body-weight  and  the 
calories  per  square  meter  of  body-surface  referred  to  weight.  Since 
both  these  bases  of  measurement  should  show  a  sexual  differentiation, 
if  such  exist,  we  have  prepared  charts  giving  these  comparisons. 
(See  figs.  50  and  51.)  The  curves  for  boys  and  girls  in  these  two 
charts  were  taken  directly  from  figures  35,  36,  42,  and  43,  and  are  here 
simply  superimposed  to  bring  out  the  sexual  differentiation,  which  is 
essentially  that  noted  with  the  weight  curves. 

To  make  an  approximate  comparison  of  the  heat  production  per 
kilogram  of  body-weight  and  per  square  meter  of  body-surface  between 
youth  and  adults,  we  have  laid  on  these  charts  lines  representing 
grossly  the  trend  of  metabolism  with  women  and  men  with  increasing 


INFLUENCE   OF   SEX   ON   METABOLISM. 


181 


weight,  as  was  done  in  figure  48  for  the  total  calories  referred  to 
weight.  It  is  highly  important  that  these  curves  should  not  be 
interpreted  as  giving  a  sharp  picture  of  the  actual  metabolic  changes 
with  increasing  weight.  Accordingly,  since  these  curves  were  drawn 
from  plots  representing  all  of  our  adult  measurements,  we  publish  at 


CALORIES  PER  KILO.  REFERRED  TO  WEIGHT. 


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FIG.  50. — Comparison  of  basal  heat  production  of  children  and  adults  per  kilogram  of 
body-weight  per  24  hours  referred  to  weight. 

this  point  the  charts  from  which  these  adult  curves  were  derived. 
(See  figs.  52,  53,  54,  and  55.)  The  laying  of  a  smoothed  curve  on 
these  charts  is,  owing  to  the  scatter  of  the  points,  extremely  difficult. 
While  the  straight  line  which  is  at  a  constant  level  hi  the  case  of  men 
when  the  heat  per  square  meter  is  referred  to  weight  (fig.  54)  would 
seem  to  be  an  admission  of  the  constancy  of  heat  production  per 


Cals. 
1200 

1100 
1000 
900 
800 
700 

600 
t 

CALORIES  PER  SQ.  M.  REFERRED  TO  WEIGHT. 

<  ^ 

i 

GIRLS  AND  WOMEN  
BOYS  AND  MEN   



/ 

\ 

"^s 

s^. 

/ 

/ 

"*-•-. 

-—  —  . 



=L 









— 

L__ 



1 





7 

1  — 

kgs.6       10       14       18      22      26      30      34      38      42      46      50      54      58     62      66      7O      7 

4       78      82      86       90     9- 

FIG.  51. — Comparison  of  basal  heat  production  of  children  and  adults  per  square  meter  of 
body-surface  per  24  hours  referred  to  weight. 

square  meter  of  body-surface  with  men,  we  believe  that  no  one  in- 
specting this  chart,  with  its  wide  scatter  of  individual  points,  can 
conclude  that  this  line,  which  represents  trend  only,  can  be  logically 
looked  upon  as  a  demonstration  of  the  general  thesis  that  the  heat 
production  per  square  meter  of  body-surface  with  man  is  constant. 
With  women  it  would  seem  as  if  a  slight  slant  to  the  line  more  closely 


182  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

fitted  the  general  trend,  but  here  again,  owing  to  the  wide  scatter  of 
the  points,  there  is  no  evidence  of  regularity  in  the  relationship  between 
heat  production  and  surface  area.  With  youth,  even  with  the  wide 
scatter  of  the  individual  points  in  figures  42  and  43,  the  lines  denoting 
the  general  trend  show  pronounced  deviation  from  a  uniformly  hori- 
zontal level. 


CALORIES  PER  KILO.  REFERRED  TO  WEIGHT. 


MEN. 


46kgs.50    54     58      62      66      70      74      78      82      86      90     94 


FIG.  52. — Basal  heat  production  of  men  per  kilogram  of  body-weight 
per  24  hours  referred  to  weight. 

Several  important  points  should  be  emphasized  in  connection  with 
the  comparisons  of  the  metabolism  of  youths  and  adults  on  all  bases 
of  comparison  as  indicated  in  figures  48,  50,  and  51.  One  is  the 
quite  remarkable  coincidence  of  the  extension  of  the  line  for  boys  with 
that  laid  down  for  men,  an  agreement  that  is  somewhat  less  striking 
in  the  case  of  the  girls  and  women.  The  data  for  the  higher-weight 
boys  and  lower-weight  men,  and  particularly  the  higher-weight  girls 
and  lower-weight  women,  are  still  altogether  too  few  to  consider  this 
part  of  the  curves  as  clearly  established.  At  the  moment  of  writing, 


Cals. 
36 


CALORIES  PER  KILO.  REFERRED  TO  WEIGHT. 


30  =, 


24 


12 


34kgs.38    42      46      50      54      58      62      66      70      74      78      82      86      90     94 

FIG.  53. — Basal  heat  production  of  women  per  kilogram  of  body-weight 
per  24  hours  referred  to  weight. 

further  experimental  data  are  being  obtained  at  the  Nutrition  Labor- 
atory for  ages  between  12  and  20  years  for  both  sexes.  Finally,  empha- 
sis must  again  be  laid  upon  the  fact  that  all  of  these  lines  represent 
at  best  only  general  trends,  particularly  with  adults.1 

From  a  consideration  of  all  of  the  charts  in  which  the  metabolism 
curves  for  boys  and  men  on  the  one  hand  and  girls  and  women  on  the 
other  are  compared,  it  is  evident  that  the  metabolism  of  boys  and 
men  is  for  practically  the  entire  period  of  life  perceptibly  and  con- 


1  See  page  132  for  description  of  method  of  sketching  curves. 


INFLUENCE   OF   SEX   ON   METABOLISM. 


183 


sistently  higher  than  that  for  girls  and  women.  While  new  data  on 
the  uncertain  period  between  the  weights  of  30  and  45  kg.  may  some- 
what modify  these  general  curves,  nevertheless  it  appears  clearly 
established  that  males  have  on  the  whole  a  higher  metabolism  than 

CALORIES  PER  SQ.  M.  REFERRED  TO  WEIGHT.  MEN. 


1050 
950 
850 

750 
4 

• 

1 

:  • 

L. 

:. 

• 

•\ 

-.'. 

•..-.; 

••  ' 

• 

. 

.' 

" 

*kgs.48  52  56  60  64   68  72   76   80  84   88  9J 

Fio.  54. — Basal  heat  production  of  men  per  square  meter  of  body-surface 
per  24  hours  referred  to  body-weight. 

females.  When  we  compare  the  calories  per  kilogram  referred  to 
weight  and  the  calories  per  square  meter  referred  to  weight,  it  can  be 
seen  that  after  a  weight  of  about  14  kg.  the  differences  between  the 
two  sexes  remain  almost  uniformly  constant  throughout  the  entire 
weight-range. 


CALORIES  PER  SQ.  M.  REFERRED  TO  WEIGHT 


WOMEN. 


650 


36kgs.40     44      48      52      56     60      64      68     72      76     80      84      88     92     96 


FIG.  55. — Basal  heat  production  of  women  per  square  meter  of  body-surface 
per  24  hours  referred  to  body-weight. 

METABOLISM   IN  PREPUBESCENCE. 

Any  discussion  of  the  sexual  differences  between  boys  and  girls 
would  be  incomplete  without  reference  to  the  important  transforma- 
tion in  sexual  life  taking  place  at  the  time  of  puberty,  a  transformation 
that,  in  the  minds  of  a  number  of  writers,  has  been  clearly  apparent 
in  the  course  of  the  general  total  metabolism.  Even  the  early  studies 
of  Andral  and  Gavarret1  gave  this  factor  serious  attention,  but  un- 
fortunately their  data  are  too  meager  to  be  of  much  value  at  this  tune. 
In  1916  there  appeared  the  first  of  two  remarkable  papers  by  Dr.  E.  F. 
Du  Bois,2  of  New  York,  in  which  the  metabolism  at  the  period  of 
development  of  boys  immediately  preceding  puberty  was  studied. 
The  importance  of  the  problem  under  consideration  can  be  no  better 
set  forth  than  by  quoting  the  initial  paragraph  of  this  paper. 


Andral  and  Gavarret,  Ann.  d.  Chim.  et  d.  Phys.,  1843,  ser.  3,  8,  p.  129. 
Du  Bois,  Arch.  Intern.  Med.,  1916,  17,  p.  887. 


184  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

"In  the  period  of  development  of  boys,  the  years  immediately  preceding 
puberty  are  of  especial  interest.  By  this  time  the  figure  has  lost  most  of 
its  childish  characteristics  and  the  mind  has  reached  a  point  of  great  in- 
telligence. Although  the  individual  has  scarcely  passed  the  half-way  mark 
in  the  years  of  growth,  and  has  only  attained  half  his  future  weight,  yet  he 
resembles  the  adult  much  more  than  he  resembles  the  infant.  At  this  stage 
the  sex  glands  have  not  yet  begun  the  rapid  development  of  puberty  with 
its  profound  effect  on  the  whole  organism.  Curiously  enough  there  is  a 
sudden  increase  in  the  rate  of  growth  which  takes  place  at  this  time.  In 
fact,  we  may  consider  boys  in  the  period  of  prepubescence  as  individuals  of 
adult  form  but  of  small  size,  growing  rapidly,  and  as  yet  scarcely  influenced 
by  the  internal  secretions  of  the  sex  glands.  The  study  of  their  respiratory 
exchanges  may  throw  light  on  many  problems." 

While  we  unfortunately  have  to  differ  with  Du  Bois  as  to  these 
experiments  meeting  the  strict  requirements  for  basal  metabolism, 
no  paper  has  called  more  attention  to  the  possibilities  of  changes  in 
metabolism  in  youth  as  compared  to  the  adult  period  than  has  this. 
We  feel  that  the  very  high  values  found  by  Du  Bois  must  have  been 
due  in  large  part  to  muscular  activity;  consequently,  a  comparison  is 
of  interest  between  his  results  and  those  of  our  observations  with  boys 
between  12  and  13  years  old,  which  were  obtained  under  conditions 
more  closely  approximating  basal. 

On  reference  to  figure  22  (page  133),  we  find  records  of  6  boys 
between  the  ages  of  12  and  13  years.  Of  these,  2  lie  above  the  pro- 
jected line  indicating  the  general  trend  of  the  metabolism,  and  4 
below.  From  an  examination  of  this  line  alone,  one  can  see  no  increase 
in  the  general  trend  of  metabolism  peculiar  to  this  age;  but  since  there 
may  be  the  reasonable  objection  that  our  boys  were  of  abnormal 
weight  for  their  age,  we  may  note  the  effect  of  computing  the  calories 
per  square  meter.  An  examination  of  figure  45  shows  us  that  of  these 
6  boys,  2  are  again  above  the  line  representing  the  general  trend  and 
4  below,  with  no  indication  of  a  supernormal  metabolism. 

While  the  greater  part  of  our  observations  were  made  with  children 
in  the  period  of  prepubescence,  a  few  observations  were  made  with  boys 
and  girls  after  puberty  was  established.  These  are  indicated  on  the 
several  charts  by  a  special  designation,  i.  e.,  by  a  square  surrounding 
the  point.  In  figure  22  only  one  boy  is  so  indicated,  the  point  lying 
somewhat  above  the  general  trend.  In  figure  45,  in  which  the  calories 
per  square  meter  of  body-surface  are  referred  to  age,  this  point  like- 
wise lies  above  the  line  for  the  general  trend.  From  this  one  observa- 
tion, therefore,  one  might  infer  that  there  was  a  slight  tendency  for  an 
increase  in  metabolism  after  the  onset  of  puberty  rather  than  prior 
to  it;  but  obviously  no  special  consideration  should  be  given  to  a 
single  observation,  especially  as  the  determined  value  is  not  much 
above  the  general  trend. 

The  influence  of  prepubescence  upon  the  metabolism  of  girls  is  like- 
wise of  special  physiological  interest.  We  note  in  figure  23,  which 


INFLUENCE   OF   SEX   ON   METABOLISM.  185 

gives  the  total  calories  referred  to  age,  that  within  the  age  limits  of 
approximately  10  to  12  years  three  points  are  specially  designated  to 
show  puberty,  one  very  considerably  above  the  general  line  and  two 
below.  With  two  of  these  girls,  puberty  w^as  well  established,  one  at 
10|  years  and  the  other  at  12  years  and  1  month,  while  with  the  third 
child,  at  12  years  and  2  months,  puberty  was  beginning.  It  was 
possible  to  make  observations  with  one  of  these  girls  (No.  239)  at 
11  years,  before  puberty  began.  At  the  earlier  age  (specially  desig- 
nated by  inclosing  the  point  in  a  diamond)  the  metabolism  was  984 
calories,  while  1  year  and  1  month  later,  after  puberty  was  established, 
it  was  1,500  calories.  Only  in  this  one  case  is  there  apparent  evidence 
of  a  striking  effect  of  puberty  itself  upon  metabolism.  An  examination 
of  the  rest  of  the  curve  shows  no  indication  of  a  pronounced  increase 
in  metabolism  during  the  prepubescent  age. 

The  evidence  with  this  one  girl  in  figure  23  is,  however,  very  decep- 
tive, since  on  reference  to  figure  27,  in  which  the  total  calories  are 
referred  to  weight,  it  is  seen  that  in  the  year  and  one  month  inter- 
vening between  the  two  observations,  this  subject  had  gained  in 
weight  practically  12  kg.  As  a  matter  of  fact,  she  had  also  increased 
14  cm.  in  height.  Accordingly,  comparison  may  not  be  made  directly 
on  the  basis  of  total  calories  referred  to  age  without  taking  into  con- 
sideration some  of  the  physical  factors.  With  the  striking  increase 
in  weight,  the  first  obvious  correction  would  be  to  consider  the  calories 
per  kilogram  of  body-weight  with  this  subject  at  the  two  ages.  This 
has  been  done  in  figure  31,  and  here  we  note  that  the  striking  differ- 
ences have  practically  disappeared,  namely:  at  the  age  of  11  years, 
the  heat  is  36  calories  per  kilogram  of  body-weight;  at  12  years  and 
1  month,  38  calories.  Precisely  the  same  relationship  holds  true  when 
we  compare  calories  per  kilogram  of  body-weight  at  different  weights, 
as  shown  in  figure  36.  Consequently,  a  portion  at  least  of  the  striking 
difference  in  total  metabolism  noted  with  this  child  before  and  after 
the  establishment  of  puberty  must  be  ascribed  to  the  pronounced 
alteration  in  body-weight. 

Having  in  mind  the  older  conception  of  the  significance  of  the  body- 
surface  area,  we  should  also  consider  the  caloric  output  per  square 
meter  of  body-surface  with  this  child.  On  reference  to  figure  47, 
where  the  values  are  compared  on  this  basis,  we  find  that  after  the 
age  of  10  years  there  is  a  wide  scatter  of  individual  points.  The  one 
girl  at  the  age  of  10|  years  with  puberty  established  shows  a  value 
considerably  below  the  general  line.  Another  at  12  years  and  2 
months,  with  puberty  just  beginning,  is  likewise  slightly  below  the 
line.  The  child  with  values  before  and  after  establishment  of  puberty 
(No.  239)  is  represented  at  the  later  age,  12  years  1  month,  when 
puberty  was  fully  established,  by  the  highest  point  on  the  chart.  The 
heat  production  per  square  meter  per  24  hours  for  this  girl  at  11  years 


186  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

was  909  calories,  while  at  12  years  and  1  month  it  had  risen  to  1,179 
calories,  or  an  increase  of  nearly  30  per  cent.  The  general  picture  is 
therefore  essentially  the  same  as  that  noted  in  figure  23  for  the  total 
calories  referred  to  age. 

When  the  caloric  output  per  square  meter  of  body-surface  is  referred 
to  body-weight,  as  in  figure  43,  a  wide  difference  in  the  heat  production 
per  square  meter  at  these  two  weights  is  exhibited.  While,  therefore, 
the  great  difference  in  total  heat  production  noted  on  the  chart  for 
total  calories  referred  to  age  (fig.  23)  is  in  large  part  removed  by  refer- 
ence to  heat  production  per  kilogram  of  body-weight  (fig.  31),  there 
still  remains  a  very  striking  difference  between  the  prepubertal  and 
pubertal  stage  when  the  heat  production  per  square  meter  is  con- 
sidered. Precisely  the  same  order  of  differences  is  to  be  observed  with 
this  girl  when  the  total  calories  are  referred  to  the  surface  and  the 
calories  per  square  meter  are  referred  to  surface  in  figures  39  and  41, 
respectively. 

What  little  evidence,  if  any,  can  be  drawn  from  these  charts  for 
boys  and  girls  as  to  the  influence  of  prepubescence  and  the  establish- 
ment of  puberty  on  metabolism  may  be  summed  up  in  the  statement 
that  prior  to  puberty  there  is  no  tendency  for  a  change  in  the  general 
trend  of  the  basal  metabolism.  The  establishment  of  puberty  in  at 
least  one  girl  resulted  in  a  relatively  high  metabolism,  which  was  made 
clear  by  measurements  both  prior  to  and  subsequent  to  the  establish- 
ment of  puberty.  Sonde"n  and  Tigerstedt1  and  Olin2  report  no  increase 
per  kilogram  or  per  square  meter  following  puberty. 

Since  with  our  boys  and  girls  we  did  not  find  the  increase  in  metab- 
olism which  Du  Bois  found,  it  becomes  necessary  for  us  to  disagree 
with  his  findings  for  boys  12  and  13  years  old,  and  we  believe  our  con- 
clusion is  justified,  that  the  prepubescent  period  is  without  significant 
effect  upon  the  metabolism  of  the  boy  or  girl.  The  evidence  regarding 
the  effect  of  puberty  fully  established  is  sufficiently  divergent  in  the 
existing  researches  to  warrant  much  further  study  on  this  important 
point.  Du  Bois's  evidence  indicates  strongly  a  decrease  in  metabolism 
following  the  prepubescent  stage.  The  very  meager  evidence  we 
possess  indicates  a  tendency  to  an  increase,  although  admittedly  this 
is  largely  based  upon  the  measurements  of  one  girl,  which  were  made 
before  and  after  the  establishment  of  puberty.  Had  not  the  question 
of  the  influence  of  puberty  upon  the  metabolism  been  raised  by  earlier 
investigators,  we  should  not  feel  that  we  were  in  any  way  justified  on 
the  basis  of  this  one  experiment  in  discussing  the  question.  We 
believe  that  the  chief  point  to  be  raised  here  is  that  further  studies 
with  children  of  this  age  are  imperative.  Such  investigation  is  now 
in  progress  at  the  Nutrition  Laboratory. 

1  Sonddn  and  Tigerstedt,  Skand.  Archiv  f.  Physiol.,  1895,  6,  p.  75. 

2  Olin,  Skand.  Archiv  f.  Physiol.,  1915,  34,  p.  432. 


PREDICTION   OF   THE    BASAL   METABOLISM   OF   YOUTH.       187 

THE  PREDICTION  OF  THE  BASAL  METABOLISM  OF  YOUTH.i 

In  the  last  analysis,  one  of  the  most  important  factors  in  a  metab- 
olism study  is  the  potentiality  of  drawing  from  the  data  a  method 
of  predicting  the  unknown  metabolism  of  a  subject.  The  establish- 
ment of  a  normal,  when  based  upon  unvarying  laws  of  either  physics 
or  chemistry,  results  in  a  standardization  of  values  that  makes  possible 
the  immediate  estimation  of  the  probable  resultant  of  any  two  or  more 
physical  factors.  In  physiology  the  normal  variation  is  so  great  as 
absolutely  to  preclude  a  mathematically  established  standard  without 
deviations  therefrom.  On  the  assumption  that  the  children  in  this 
study  were  normal  in  the  commonly  accepted  use  of  that  word,  we 
do  find,  however,  that  the  total  metabolism  follows  a  reasonably  uni- 
form curve  in  some  of  the  relationships  studied. 

While  nearly  all  of  our  numerous  charts  show  a  wide  scatter  of 
points,  certain  charts  are  characterized  by  a  fairly  close  grouping  of 
points  around  the  hypothetical  line  indicating  the  general  trend. 
These  are  specially  the  charts  showing  the  total  calories  referred  to 
body-weight  for  both  boys  and  girls  (figs.  26  and  27,  pages  140  and  142) 
and  the  total  calories  referred  to  actually  measured  surfaces  for  both 
boys  and  girls  (figs.  38  and  39,  pages  161  and  164).  From  these 
curves  it  would  appear  that  it  is  not  impossible  to  predict  with 
reasonable  accuracy  the  probable  basal  metabolism  of  a  child  when 
either  the  weight  or  the  measured  body-surface  is  known.  The  body- 
weight  is  very  readily  and  frequently  obtained,  but  the  Du  Bois 
method  of  measuring  the  body-surface,  while  very  specific  and  readily 
acquired  after  a  little  careful  consideration  of  the  directions,  never- 
theless requires  such  an  extensive  series  of  measurements  as  to  make 
its  general  use  impractical. 

In  general,  the  grouping  of  the  individual  points  about  the  curves 
in  figures  26,  27,  38,  and  39  is  often  so  seemingly  compact  as  to  suggest 
that  the  curve  sufficiently  represents  the  general  trend  for  it  to  serve 
as  a  foundation  for  the  prediction  of  the  basal  metabolism  of  unknown 
subjects.  Still,  on  closer  inspection,  the  scatter  of  individual  points 
is  noted  to  be  considerable.  One  deceptive  feature  of  these  curves, 
making  an  intelligent  comparison  with  curves  for  adults  difficult,  is 
the  fact  that  the  deviation  from  the  general  line  varies  greatly  as  to 
its  percentage  value  according  to  the  weight  of  the  individual  or  the 
size  of  the  surface  area;  consequently  it  is  only  with  percentage 
relationships  that  one  may  properly  deal. 

From  an  inspection  of  the  curves  for  calories  referred  to  both  surface 
and  weight,  it  is  difficult  to  estimate  with  the  eye  as  to  which  basis, 
i.  e.}  surface  or  weight,  would  give  the  better  method  for  prediction, 
although  in  the  earlier  consideration  of  these  curves  we  noted  that 

>A  preliminary  discussion  of  this  point  has  recently  appeared:   Benedict,  Proc.  Nat.  Acad. 
Sci.,  1920,  6,  p.  7. 


188  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

there  seemed  to  be  a  somewhat  wider  dispersion  of  points  about  the 
curves  for  surface  than  about  the  curves  for  weight.  For  an  exact 
analysis  of,  (1)  the  suitability  of  these  curves  for  prediction,  and  (2)  of 
the  relative  merits  of  surface  and  weight  curves  for  prediction,  mathe- 
matical treatment  of  each  child  on  the  two  bases  of  weight  and  surface 
referred  to  total  calories  is  essential;  consequently  we  have  prepared 
two  tables  for  the  boys  and  girls,  respectively,  giving  the  essential 
physical  data  for  the  individual  children,  and  the  values  for  both  the 
measured  heat  and  the  heat  predicted  on  the  two  bases  of  weight  and 
surface.  Since  we  are  testing  the  accuracy  of  our  general  curves  for 
the  prediction  of  heat,  the  differences  between  the  predicted  and  actual 
heat  are  given  in  these  tables  for  both  methods  of  prediction  on  the 
basis  of  the  predicted  less  the  actual,  so  that  if  the  prediction  is  lower 
than  the  actual  the  difference  will  be  indicated  by  a  minus  sign.  The 
percentage  differences  are  also  given,  since  percentage  values  can 
alone  be  used  for  the  comparison  of  children  of  various  sizes. 

In  addition  to  the  data  for  the  predicted  heat  on  the  bases  of  weight 
and  surface,  we  have  employed  a  third  method  of  prediction  for  the 
boys,  in  which  use  was  made  of  the  multiple  prediction  formula  of 
Harris  and  Benedict1  as  proposed  by  them  for  the  prediction  of  the 
most  probable  total  heat  production  of  men.  Exactly  the  same 
treatment  with  regard  to  the  differences  between  predicted  and 
actual,  as  well  as  the  percentage  differences,  is  accorded  this  method 
of  prediction.  Thus  we  have  in  the  tables  the  actual  total  heat 
production  per  24  hours  of  each  child  and  then  (by  the  three  methods 
of  prediction)  the  most  probable  heat  production  of  a  child  of  similar 
weight  or  (in  the  case  of  surface)  of  similar  surface,  taken  from  the 
corresponding  curve.  The  differences  of  the  actual  from  the  smoothed 
curve  values  are  then  noted  and  recorded  and  the  percentage  values 
found.  Since  with  the  first  two  methods  of  prediction,  i.  e.,  those 
from  curves,  the  smoothed  curve  is  nothing  more  than  an  attempt  to 
equalize  all  the  inequalities  in  the  values,  theoretically  there  should 
be  practically  the  same  number  of  plus  and  minus  differences  in  the 
whole  series,  and  in  any  event  the  sum  of  the  plus  or  minus  differences 
should  practically  equal  zero. 

PREDICTED  HEAT  FROM  TOTAL  CALORIES  REFERRED  TO  WEIGHT 

(BOYS). 

The  predicted  heat  for  boys,  based  upon  the  curve  for  total  calories 
referred  to  weight  (see  fig.  26)  is  given  in  table  32  and  may  first  be 
considered.  A  superficial  inspection  of  the  table  shows  an  approxi- 
mately equal  distribution  of  plus  and  minus  signs.  While  this  wrould 

1  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919.  In  this  monograph  the  differ- 
ences were  computed  by  deducting  the  predicted  values  from  the  actual,  instead  of  the  actual 
values  from  the  predicted  as  in  the  present  report. 


PREDICTION    OF   THE   BASAL   METABOLISM   OF   YOUTH.       189 

tend  to  indicate  that  the  differences  between  individuals  were  in  the 
main  eliminated  in  drawing  the  curve,  special  consideration  should  be 
given  to  the  numerical  and  percentage  differences  of  the  predicted  less 
the  actual  heat.  The  numerical  differences  are  expressed  in  column  g 
of  table  32  and  vary  from  0  to  as  high  as  177  calories.  Since  there 
was  a  very  wide  variation  in  the  heat  actually  measured,  i.  e.,  from  a 
minimum  of  163  calories  with  two  of  the  youngest  boys  to  as  high 
as  1,401  calories  with  the  oldest  boy,  the  percentage  differences  alone 
are  of  value  for  comparative  purposes.  The  average  percentage  differ- 
ence for  the  whole  series  of  boys,  as  given  in  table  33,  indicates  that 
the  total  heat  can  be  predicted  from  the  curve  for  calories  referred 
to  weight  with  a  deviation  of  db7.4  per  cent.  Although  an  average 
error  of  this  magnitude  may  be  considered  as  large,  it  must  be  remem- 
bered that  the  data  for  growing  children  are  extraordinarily  few. 
Hence,  if  we  are  to  take  advantage  of  this  series  of  observations,  the 
hint  given  by  the  general  trend  of  the  line  in  figure  26  may  on  the  whole 
be  regarded,  provided  that  too  much  emphasis  is  not  placed  upon  this 
method  of  prediction. 

On  inspection  of  the  percentage  deviations  in  table  32,  we  find  that 
the  differences  of  the  predicted  from  the  actual  are  rather  considerable 
in  some  instances,  there  being  deviations  with  7  boys  of  20  per  cent 
or  more.  In  all  of  these  seven  instances  the  weight  of  the  boys  is 
10.7  kg.  or  below,  suggesting  that  the  error  of  prediction  with  small 
children  is  much  greater  than  it  is  with  the  larger -children.  Appar- 
ently some  weight  not  far  from  10  kg.  represents  an  approximate 
dividing-line  between  a  reasonably  close  prediction  and  a  much  more 
gross  prediction.  If  we  use  10  kg.  as  an  arbitrary  dividing-line,  and 
calculate  the  average  deviation  of  the  predicted  heat  from  the  measured 
heat  for  children  weighing  10  kg.  and  above,  we  find  this  average 
deviation  to  be  ±6.3  per  cent.  (See  table  33.)  For  the  boys  under 
10  kg.,  we  find  the  average  percentage  deviation  to  be  ±8.7  per  cent. 
Thus,  what  is  obvious  to  the  eye,  both  with  regard  to  the  dispersion 
of  points  and  to  the  general  magnitude  of  the  percentage  differences  in 
column  h  of  table  32,  is  amply  verified  by  a  calculation  of  the  average 
percentage  deviation  of  the  predicted  values  from  the  actually  observed 
values. 

That  some  other  weight  than  10  kg.  may  not  be  slightly  better, 
mathematically,  for  a  division-line  is  not  disproved,  but  for  practical 
purposes  this  division  seems  to  be  all  that  the  calculations  justify. 
To  test  the  theory  that  some  other  weight  might  be  better  for  division 
purposes,  the  percentage  differences  have  been  computed  for  boys 
weighing  15  kg.  and  above.  On  this  basis  we  find  that  the  prediction 
error  is  slightly  less — that  is,  it  now  becomes  ±5.8  instead  of  ±6.3  per 
cent.  Since,  however,  we  purpose  predicting  the  heat,  not  from  a 
formula,  but  by  drawing  points  from  this  curve,  the  lessening  of  the 


190  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


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PREDICTION   OF   THE   BASAL   METABOLISM   OF   YOUTH.       191 


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192  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


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PREDICTION    OF   THE   BASAL   METABOLISM   OP   YOUTH.       193 


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194  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


percentage  deviation  simply  means  that  when  the  body-weight  is 
above  15  kg.,  the  error  of  prediction  is  slightly  less  than  when  it  is 
between  15  and  10  kg.,  and  considerably  less  than  with  boys  under 
10kg. 

TABLE  33. — Comparison  of  the  actual  basal  metabolism  of  boys  with  the  metabolism  predicted 
(a)  from  body-weight,1  (b)  from  body-surf  ace  f  and  (c)  from  the  adult  masculine  normal 
(multiple  prediction)  standard.3  (Average  values.4) 


Deviation 

Basis 

Number 

Actual 

Predicted 

Predicted 

of 

Group. 

of 

of 

heat 

heat 

less 

predicted 

prediction. 

boys. 

per  24  hrs. 

per  24  hrs. 

actual. 

from 

actual. 

cats. 

cols. 

cats. 

p.ct. 

All  boys               

Weight  

128 

652 

657 

±43 

±7.4 

Below  10  kg  

Do  

60 

364 

368 

±30 

±8.7 

Above  10  kg. 

Do  

68 

907 

911 

±54 

±6.3 

All  boys 

Surface  

128 

652 

654 

±46 

±7.5 

Below  0.45  sq.  m. 

Do.             .    . 

52 

344 

342 

±25 

±7.7 

Above  0.45  sq.  m. 

Do. 

76 

863 

867 

±59 

±7.3 

Above  10  kg 

Multiple  predic- 

tion standard 

68 

907 

901 

±56 

±6.3 

1  See  figure  26,  p.  140,  and  table  36,  p.  206. 

*  See  figure  38,  p.  161. 

•  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  227. 
4  Averages  obtained  from  data  in  table  32,  pp.  190  to  193. 

A  comparison  of  this  method  of  prediction  may  be  made  with  the 
results  of  recent  attempts  by  the  Nutrition  Laboratory  to  predict  the 
metabolism  of  male  adults.  By  means  of  a  multiple-prediction  formula 
derived  from  the  analysis  of  the  basal  metabolism  of  136  men,  a  group 
of  31  college  students  was  tested  on  this  basis  and  the  results  com- 
pared with  the  results  of  actual  measurements.1  The  predictions 
were,  on  the  average,  within  ±5.3  per  cent,  a  value  percepibly  better 
than  the  ±6.3  per  cent  noted  from  the  predictions  with  the  boys.2 
This  comparison  is,  however,  not  quite  fair,  since  these  college  students 
were  nearly  all  20  to  26  years  of  age,  and  were  unquestionably  more 
homogeneous  than  a  group  of  children  ranging  in  age  from  a  few  months 
to  15  years.  We  may  still  feel,  therefore,  that  on  the  whole  the  pre- 
diction of  the  metabolism  of  children  from  the  curve  in  figure  26  is 
not  greatly  inferior  to  that  for  the  best  existing  method  of  prediction 
of  the  values  for  adults. 

PREDICTED  HEAT  FROM  TOTAL  CALORIES  REFERRED  TO  SURFACE 

(BOYS). 

In  table  32  the  values  have  also  been  incorporated  for  the  heat  pre- 
dicted from  the  curve  for  total  calories  referred  to  surface  as  accurately 
measured  by  the  Du  Bois  method.  (See  fig.  38,  page  161.)  Giving 

1  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  234. 

2  The  fact  that  Harris  and  Benedict  computed  these  differences  by  deducting  the  predicted 

from  the  actual  heat  values  does  not  affect  the  percentage  in  this  case. 


PREDICTION    OF   THE   BASAL   METABOLISM   OF   YOUTH.       195 

our  attention  first  to  the  actual  differences  as  shown  in  column  j,  we 
find  that  they  range  from  0  to  as  high  as  191  calories;  but  realizing 
the  very  great  differences  in  the  actual  heat  production,  we  again 
note  that  percentage  differences  alone  can  be  considered  for  com- 
parative purposes.  Exactly  the  same  reasoning  with  regard  to  the 
effect  of  the  curve  in  smoothing  out  plus  and  minus  differences  in 
the  individual  points  obtains  here,  namely,  that  we  would  expect  to 
find  essentially  the  same  number  of  plus  as  minus  values,  and  a  super- 
ficial inspection  of  the  table  bears  this  out. 

On  the  basis  of  weight,  7  instances  were  noted  in  which  the  per- 
centage difference  was  20  per  cent  or  more,  while  the  heat  based  on  the 
surface  gives  but  5  instances.  All  but  one  of  these  are  with  children 
whose  body-weight  is  10.7  kg.  or  below.  This  observation  has  two 
important  features:  First,  it  confirms  the  view  previously  expressed 
that  the  error  of  prediction  is  largest  with  the  children  of  small  weight. 
Second,  it  implies  that,  so  far  as  extreme  errors  are  concerned,  the 
prediction  by  surface  is  somewhat  better  than  the  prediction  by  weight. 
It  is,  however,  only  after  a  consideration  of  all  the  data  that  one  can 
draw  final  conclusions.  With  all  the  series  of  boys  the  average  per- 
centage deviation  of  predicted  from  the  actual  is  ±7.5  per  cent. 
(See  table  33.)  Thus  it  appears  that  while  the  number  of  cases  of 
extreme  error  was  less  when  the  measured  surface  was  used  in  pre- 
dicting the  total  calories,  on  the  average  this  method  of  prediction 
gives  slightly  greater  error  than  when  the  calories  are  referred  to 
weight. 

Our  general  impression  that  the  error  of  prediction  is  greater  with 
children  with  smaller  surface  is  sufficiently  substantiated  to  justify 
our  making  a  division  of  the  values  and  considering  boys  with  a  surface 
area  below  0.45  square  meter  in  one  group  and  those  above  this  area 
in  another.  This  division  will  be  not  unlike  the  comparison  on  the 
basis  of  weight,  since  a  body-weight  of  10  kg.  corresponds  approxi- 
mately to  a  surface  area  of  0.45  square  meter.  The  results  for  this 
division  are  also  given  in  table  33  and  show  that  with  the  boys  below 
0.45  square  meter  of  surface,  the  error  of  prediction  is  ±7.7  per  cent, 
while  the  boys  above  this  area  have  a  slightly  better  percentage, 
namely,  ±7.3  per  cent.  It  thus  appears  that  with  the  smaller  boys 
the  error  of  prediction  is  somewhat  greater  by  weight  than  by  surface, 
i.  e.,  ±8.7  per  cent  as  compared  with  ±7.7  per  cent.  This  fact,  taken 
alone,  would  imply  a  greater  correlation  between  body-surface  area 
and  heat  production  than  between  body-weight  and  heat  production. 
On  the  other  hand,  with  the  boys  weighing  10  kg.  and  above  and  with  a 
surface  area  of  0.45  square  meter  and  above,  we  find  that  the  error 
of  prediction  is  1  per  cent  greater  when  surface  area  is  used — that  is, 
±7.3  per  cent  for  prediction  by  surface  as  compared  with  ±6.3  per 
cent  by  weight.  With  boys  with  a  body-weight  of  10  kg.  or  above, 


196  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

therefore,  more  satisfactory  results  may  be  obtained  in  predicting  the 
metabolism  from  a  curve  in  which  the  calories  are  referred  to  weight 
than  from  a  curve  in  which  the  calories  are  referred  to  surface. 

If  we  employ  another  line  of  division,  as  was  done  in  making  com- 
parisons on  the  weight  basis,  and  use  a  surface  area  of  0.65  square 
meter  as  the  dividing-line,  we  find  that  the  average  percentage  error 
for  boys  with  this  area  or  above  is  somewhat  lower,  being  ±6.8  per 
cent,  as  compared  with  ±7.3  per  cent  with  the  division  at  0.45  square 
meter. 

It  should  be  borne  in  mind  that  the  curves  used  for  predicting  the 
metabolism  were  arbitrarily  laid  on  these  charts,  and  represent  simply 
the  resultant  personal  impressions  of  five  skilled  workers  with  metab- 
olism curves.  They  are  not  based  upon  a  mathematical  analysis  of 
the  points  as  a  whole,  and  such  an  analysis  has  not  been  attempted. 
Still,  we  believe  that  the  curves  have  a  sufficient  degree  of  accuracy 
to  show  that  there  is  a  definite  superiority  in  the  prediction  from  the 
curve  for  calories  versus  weight  to  that  from  the  curve  of  calories 
versus  surface.  It  thus  becomes  of  physiological  interest  to  recall  that, 
as  a  result  of  metabolism  measurements  upon  adults,  it  is  commonly 
believed  that  the  relationship  between  weight  and  metabolism  is  by 
no  means  so  satisfactory  as  the  relationship  between  surface  area  and 
metabolism.  The  comparison  of  the  predicted  and  measured  heat 
values  for  these  boys  appears  to  show  that  the  prediction  of  the  metab- 
olism from  the  weight  is  not  only  as  good  as  that  from  surface,  even 
though  we  are  dealing  here  with  actually  measured  surfaces,  but 
that  it  is  actually  a  somewhat  better  method  of  prediction  for 
children  over  10  kg.  Hence  these  curves  and  predictions  establish  the 
fact  that  the  correlation  between  weight  and  basal  metabolism  is,  at 
least  with  boys  over  10  kg.  in  weight,  of  a  higher  order  than  the  cor- 
relation between  measured  body-surface  and  metabolism. 

In  the  analysis  of  the  basal  metabolism  data  for  136  men,  the 
average  deviation  without  regard  to  sign  of  the  predicted  from  the 
observed  values  was  in  the  case  of  men,  when  calculated  from  the 
body-weight  by  equations,  97.6  calories.1  Since  the  average  heat  pro- 
duction of  these  men  was  1,632  calories,1  this  gives  an  average  per- 
centage deviation  of  essentially  6  per  cent.  With  boys  from  10  to 
41  kg.,  we  find  from  the  curve  of  total  calories  referred  to  weight  a 
deviation  of  ±6.3  per  cent.  It  is  of  significance  that  the  marvelous 
changes  in  muscle,  bone,  and  fat — all  changes  due  to  the  rapid  period 
of  growth  through  which  our  study  of  boys  progresses — should  not 
alter  appreciably  the  percentage  error  of  prediction  from  the  general 
curve  so  as  to  make  it  any  greater  than  that  with  men.  In  other 
words,  in  spite  of  the  great  changes  due  to  growth,  the  average  error 
is  hardly  greater  for  boys  than  with  adults,  with  whom  growth  altera- 
tions have  practically  ceased. 

1  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  pp.  180  and  182. 


PREDICTION   OF   THE   BASAL   METABOLISM   OF   YOUTH.       197 

COMPARISON   OF  THE  PREDICTED  METABOLISM   OF  BOYS  AND  MEN. 

This  discussion  thus  far  has  been  based  upon  methods  of  prediction 
and,  indeed,  comparison  between  youths  and  adults  regarding  but 
one  physical  factor  at  a  tune,  i.  e.,  weight  or  surface.  Since  with 
adults  it  has  been  shown  that  weight,  stature,  and  age  have  each  an 
independent  influence  on  basal  metabolism,  the  comparison  of  youth 
with  adults  will  not  be  complete  unless  the  simultaneous  use  of  these 
factors  is  made. 

In  an  earlier  report,1  the  metabolism  of  groups  of  boys  studied  by 
Magnus-Levy  and  Falk  and  by  Du  Bois  was  compared  to  the  com- 
puted metabolism  of  boys  by  means  of  the  prediction  formula  derived 
from  the  analysis  of  136  men,  which  took  into  consideration  weight, 
stature,  and  age  changes.  It  was  found  that  the  values  for  the  actually 
measured  metabolism  of  these  boys  was  invariably  very  much  higher 
than  those  computed  by  the  multiple-prediction  formula,  which 
assumed  that  their  metabolism  was  the  same  as  that  of  adults  of  like 
sex,  height,  weight,  and  age.  The  Du  Bois  boys,  in  particular,  showed 
an  actual  measured  metabolism  very  much  greater  than  that  predicted 
from  the  formula  for  men  proposed  by  Harris  and  Benedict.  This 
was  in  line  with  Du  Bois's  interpretation  of  his  own  results  on  the  basis 
of  the  heat  production  per  square  meter.  In  view  of  the  calculated 
results  obtained  for  boys  by  Harris  and  Benedict,  it  seems  desirable 
to  compute  the  metabolism  of  the  boys  in  our  study  with  the  multiple- 
prediction  formula  for  adults,  for  while  the  curves  in  figures  50  and  51 
show  a  perceptibly  higher  heat  production  per  kilogram  of  body-weight 
and  per  square  meter  of  body-surface  for  boys  than  with  men,  it  will 
be  important  to  note  if  the  resultant  effect  of  the  three  varying  factors, 
age,  weight,  and  height,  as  included  in  the  prediction  by  the  planar 
equations,  is  at  all  in  conformity  with  the  trend  in  metabolism  noted 
with  adults.  We  have,  therefore,  computed  the  metabolism  of  all 
of  these  boys,  using  the  multiple-prediction  formula  for  men,2  i.  e., 
heat  equals  66.4730  +  13.7516w  +  5.0033s  -  6.7550a.  These  val- 
ues have  been  recorded  in  table  32,  together  with  the  differences 
between  the  predicted  and  actual,  both  numerical  and  percentage. 

Although  special  emphasis  has  been  laid  in  the  foregoing  discussion 
upon  boys  with  body-weights  of  10  kg.  and  over,  those  with  smaller 
body-weights  are  likewise  included.  With  the  very  young  children, 
it  will  be  seen  that  by  the  multiple-prediction  method  the  error  is 
practically  +100  per  cent.  The  metabolism  as  predicted  is  found  to 
be  too  high  in  every  instance  until  the  boy  No.  138,  with  an  age  of 
10  months  and  3|  weeks,  is  studied,  when  a  reversal  in  sign  is  found. 
Subsequently,  the  predicted  metabolism  seems  to  be  for  the  most 
part  not  far  from  that  actually  measured,  showing  plus  and  minus 
values  in  about  equal  numbers. 

1  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  pp.  237  and  238. 

2  Ibid.,  p.  227. 


198  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

A  more  careful  analysis  may  be  made  by  comparing  the  actual  heat 
produced  per  24  hours,  on  an  average,  for  boys  weighing  10  kg.  and 
above,  with  the  predicted  metabolism  calculated  from  the  multiple- 
prediction  formula.  These  average  values  are  shown  in  table  33, 
in  which  we  find  that  the  average  predicted  metabolism  is  within  ±56 
calories,  or  a  percentage  deviation  of  predicted  from  actual  of  ±6.3 
per  cent. 

We  thus  have  here  a  prediction  of  the  metabolism  of  young  boys, 
based  upon  the  multiple-prediction  standard  of  adults,  which  shows 
for  the  boys  weighing  10  kg.  or  over  a  remarkable  uniformity  with 
that  observed  from  the  curve  for  calories  referred  to  weight.  While 
Harris  and  Benedict,  in  putting  forth  their  multiple-prediction  methods, 
specifically  stated  that  its  extension  to  youth  under  16  years  of  age 
was  problematical,  it  appears  that  this  formula  applies  to  males  of  all 
ages  of  approximately  1  year  and  over.  Considering  the  rapid  changes 
in  weight  and  stature  as  compared  with  the  change  in  age  which  takes 
place  in  this  short  period  from  1  to  13  years,  it  is  an  astonishing  agree- 
ment with  the  masculine  adult  prediction  standards.  Below  the  age 
of  1  year  it  is  clear  that  the  formula  does  not  hold  true,  and  the  curves 
of  either  weight  referred  to  metabolism  or  of  surface  referred  to  meta- 
bolism must  be  relied  upon  for  prediction. 

The  multiple-prediction  equations  which  involve  factors  for  age, 
weight,  and  height  do  not,  however,  better  the  situation,  sh>ce  taking 
all  these  factors  into  consideration  gives  us  a  prediction  with  an 
error  identical  with  that  when  the  values  obtained  from  the  curve 
in  figure  26  for  weight  alone  are  considered,  i.  e.,  ±6.3  per  cent.  It 
should  be  remembered  in  this  connection  that,  during  this  period  of 
growth,  the  factors  of  age,  weight,  and  stature  are  intimately  corre- 
lated, very  much  more  so  than  is  the  case  with  adults.  Adults  weigh- 
ing 70  kg.  are  much  more  likely  to  vary  in  stature  than  boys  of  30  kg. 
Similarly,  adults  weighing  70  kg.  may  vary  in  age  from  early  youth 
to  old  age,  while  the  variation  in  age  of  boys  weighing  30  kg.  will  be 
very  much  less.  It  is  thus  probable  that  the  body-weights  of  boys 
automatically  include  the  variations  in  age  and  stature.  For  practical 
purposes,  therefore,  and  until  the  metabolism  of  children  is  given 
biometric  analysis,  the  prediction  of  the  total  basal  metabolism  of 
boys  10  kg.  and  above  may  be  made  with  a  reasonable  degree  of 
accuracy  directly  from  the  curve  based  upon  body-weight. 

PREDICTED  HEAT  FROM  TOTAL  CALORIES  REFERRED  TO 
WEIGHT  (GIRLS). 

While  the  charts  that  have  been  discussed  thus  far  give  little  indi- 
cation of  sexual  differentiation  in  the  accuracy  or  ease  of  prediction 
of  the  metabolism  of  girls  as  compared  with  boys,  it  has  seemed  desir- 
able to  consider  the  boys  and  girls  separately  in  regard  to  the  prediction 


PREDICTION   OF   THE   BASAL   METABOLISM    OF   YOUTH.       199 

TABLE  34. — Comparison  of  the  actual  basal  metabolism  of  girls  with  that  predicted:  (a)  by  the 
curve  for  "Total  calories  referred  to  weight";1  and  (6)  by  the.  curve  for  "Total  calories 
referred  to  surface."2 


Sub- 
ject 
No. 

(a) 
Age. 

Body-weight  (without  ^ 
clothing). 

(«) 

+i 

,£J 

•3 

w 

Body-surface  (Du  Bois  linear  ^ 
formula). 

(e) 

1 

3 

! 

Is 

1 

••< 

Heat  per  24  hrs. 
predicted  from 
curve  for  "Total 
calories  referred 
to  weight."1 

Heat  per  24  hrs. 
predicted  from 
curve  for  "Total 
calories  referred 
to  surface."2 

(/) 

1 

*o 

I 

(0) 

|f 

.Sb 

11 

(h) 

II 
jl 

0) 

i 
1 

(/) 
8^ 

si 

11 

(As) 

lisr 

II 

S3  '*"" 

49 
116 
26 
111 
113 
110 
2 
123 
109 
12 
131 
35 
113 
48 
120 
127 
35 
122 
139 
145 
131 
48 
113 
151 
160 
134 
140 
122 
131 
123 
139 
135 
165 
113 
152 
123 
139 
160 
35 
163 
144 
166 

11  days  
l£  mos  
10  days  
13  days  
3£  wks  
13  days  

kilos. 
2.68 
2.99 
3.56 
3.57 
3.65 
3.71 
3.73 
3.85 
3.86 
4.20 
4.34 
4.42 
4.55 
4.81 
4.90 
5.03 
5.07 
5.15 
5.19 
5.25 
5.27 
5.54 
5.54 
5.64 
5.90 
5.99 
6.02 
6.03 
6.08 
6.09 
6.11 
6.17 
6.24 
6.49 
6.52 
6.75 
7.00 
7.05 
7.17 
7.63 
7.91 
7.92 

cm. 

48.5 

50.0 
53.0 
53.0 
51.0 
53.0 
53.5 
51.5 
53.0 
55.5 
54.0 
57.5 
56.0 
58.0 
57.5 
58.5 
58.5 
63.0 
62.0 
58.0 
61.0 
63.0 
60.0 
62.5 
64.0 
60.0 
62.5 
62.0 
63.0 
65.0 
63.0 
63.0 
66.5 
65.5 
65.0 
67.0 
65.5 
64.5 
63.0 
62.0 
68.5 

sq.  m. 
.20 
.21 
.24 
.24 
.25 
.25 
.25 
.24 
.25 
.27 
.25 
.28 
.28 
.29 
.30 
.29 
.30 
.31 
.31 
.30 
.31 
.32 
.33 
.33 
.34 
.34 
.32 
.35 
.33 
.34 
.35 
.35 
.37 
.36 
.36 
.35 
.38 
.38 
.38 
.40 
.42 
.41 

cafe. 
139 
163 
185 
200 
173 
182 
152 
235 
200 
199 
235 
198 
207 
211 
274 
255 
223 
257 
315 
317 
311 
388 
289 
355 
417 
331 
334 
329 
353 
312 
325 
333 
338 
351 
357 
410 
406 
492 
329 
375 
353 
505 

cola. 
124 
149 
189 
190 
196 
200 
201 
210 
210 
233 
242 
247 
256 
273 
279 
287 
290 
295 
297 
301 
303 
320 
320 
327 
344 
349 
351 
352 
354 
355 
356 
359 
363 
377 
379 
391 
405 
408 
414 
440 
455 
456 

cala. 
-  15 
-  14 
+     4 
-  10 
+  23 
+  18 
+  49 
-  25 

+  10 

+  34 
+     7 
+  49 
+  49 
+  62 
+     5 
+  32 
+  67 
+  38 
-  18 
-   16 
-     8 
-  68 
+  31 
-  28 
-  73 
+  18 
+  17 
+  23 
+     1 
+  43 
+  31 
+  26 
+  25 
+  26 
+  22 
-  19 
-     1 
-  84 
+  85 
+  65 
+  102 
-49 

-10.8 
-  8.6 
+  2.2 
-  5.0 
+  13.3 
+  9.9 
+32.2 
-10.6 
+  5.0 
+17.1 
+  3.0 
+24.7 
+23.7 
+29.4 
+  1.8 
+  12.5 
+30.0 
+  14.8 
-  5.7 
-  5.0 
-  2.6 
-17.5 
+10.7 
-  7.9 
-17.5 
+  5.4 
+  5.1 
+  7.0 
+  0.3 
+13.8 
+  9.5 
+  7.8 
+  7.4 
+  7.4 
+  6.2 
-  4.6 
-  0.2 
-17.1 
+25.8 
+  17.3 
+28.9 

cats. 
130 
150 
187 
188 
201 
198 
200 
194 
207 
229 
205 
243 
243 
265 
271 
262 
281 
288 
293 
281 
289 
307 
320 
313 
334 
331 
302 
341 
321 
330 
346 
341 
373 
359 
359 
338 
391 
380 
393 
415 
441 
424 

cols. 
-     9 
-  13 
+     2 
-   12 
+  28 
+  16 
+  48 
-  41 
+     7 
+  30 
-  30 
+  45 
+  36 
+  54 
-     3 
+     7 
+  58 
+  31 
-  22 
-  36 
-  22 
-  81 
+  31 
-  42 
-  83 
±     0 
-  32 
+  12 
-  32 
+  18 
+  21 
+    8 
+  35 
+     8 
+     2 
-  72 
-  15 
-112 
+  64 
+  40 
+  88 
-  81 

-  6.5 
-  8.0 
+  1.1 
-  6.0 
+  16.2 
+  8.8 
+31.6 
-17.4 
+  3.5 
+15.1 
-12.8 
+22.7 
+  17.4 
+25.6 
-   1.1 
+  2.7 
+26.0 
+  12.1 
-  7.0 
-11.4 
-  7.1 
-20.9 
+10.7 
-11.8 
-19.9 
±  0.0 
-  9.6 
+  3.6 
-  9.1 
+  5.8 
+  6.5 
+  2.4 
+  10.4 
+  2.3 
+  0.6 
-17.6 
-  3.7 
-22.8 
+  19.5 
+  10.7 
+24.9 
-16.0 

10  days  
2  mos.  1  wk. 

12£  days 

9  days 

3  mos. 

8  days  
1  mo.  3^  wks. 

1  mo.  1  wk  
2  mos  
2  mos.  3|  wks  
1  mo.  1  wk  
2  mos.  1  wk  
4^  mos  

5  mos  

4  mos.  1?  wks  
2  mos.  3  wks  
4  mos.  . 

6  mos. 

7§  mos. 

4  mos. 

4  mos.  3  wks  
3  mos.  3|  wks  
7  mos.  2j  wks  
6  mos.  1  wk  
6  mos.  1  wk  
4  mos  
8  mos.  3  wks  
5  mos.  3  wks  
6  mos  
8  mos.  3  wks  
7  mos  
10  mos  
4  mos  
8  mos.  1  wk  
5  mos  
9  mos.  1  wk  

1  See  figure  27,  p.  142,  and  table  36,  p.  206. 

*  See  figure  39,  p.  164. 

200     METABOLISM   AND   GROWTH   FROM   BIRTH   TO   PUBERTY. 


TABLE  34. — Comparison  of  the  actual  basal  metabolism  of  girls  with  that  predicted:  (a)  by  the 
curve  for  "Total  calories  referred  to  weight";1  and  (6)  by  the  curve  for  "Total  calories 
referred  to  surface"2 — Continued. 


Sub- 
ject 
No. 

(a) 
Age. 

Body-weight  (without  -5- 
clothing)  . 

to 

4 
3 

Body-surface  (Du  Bois  linear  ^~- 
formula). 

Actual  heat  per  24  hrs.  £ 

Heat  per  24  hrs. 
predicted  from 
curve  for  "Total 
calories  referred 
to  weight."1 

Heat  per  24  hrs. 
predicted  from 
curve  for  "Total 
calories  referred 
to  surface."2 

(/) 

(f) 

it 

all 

83 
&§ 

(« 

i"5T 

Q>  

If 

|x 

•g  &o 

m    O 

PH  g 

CO 

1 

(/) 

£-£ 

5 

£  lo- 

(*) 

1! 
Is 
II 

162 
127 
160 
171 
139 
146 
167 
172 
146 
127 
145 
166 
173 
171 
139 
172 
122 
145 
144 
173 
171 
139 
174 
172 
166 
145 
166 
171 
139 
178 
166 
145 
139 
139 
166 
171 
179 
139 
180 
145 
190 
183 
145 
184 
181 

kilos. 
8.00 
8.11 
8.12 
8.18 
8.29 
8.30 
8.52 
8.80 
9.04 

cm. 
69.5 
67.0 
68.5 
73.5 
70.0 
68.0 
69.0 
74.5 
71.0 
73.0 
70.0 
74.5 
72.0 
76.5 
76.0 
77.0 
78.5 
72.5 
67.5 
78.0 
85.5 
82.0 
79.0 
80.0 
80.0 
76.0 
88.0 
89.5 
88.0 
92.0 
88.5 
80.0 
92.5 
96.0 
92.5 
100.0 
98.5 
99.0 
93.5 
86.5 
103.5 
97.5 
94.0 
103.0 
98.5 

sq.  TO. 
0.41 
.42 
.41 
.42 
.42 
.43 
.46 
.46 
.43 
.48 
.46 
.49 
.46 
.47 
.48 
.51 
.51 
.52 
.52 
.52 
.49 
.54 
.54 
.55 
.53 
.56 
.58 
.58 
.59 
.61 
.60 
.62 
.65 
.64 
.60 
.62 
.65 
.67 
.69 
.67 
.69 
.65 
.67 
.72 
.70 

cals. 
413 
468 
522 
502 
419 
360 
522 
568 
419 
549 
474 
559 

606 
528 
686 
597 
508 
445 
614 
643 
531 
604 
712 
597 
518 
655 
735 
590 
543 
692 
600 
607 
655 
686 
657 
560 
624 
640 
633 
637 
673 
590 
715 
771 

cals. 
460 
464 
465 
467 
472 
472 
481 
492 
502 
502 
508 
508 
509 
517 
527 
534 
544 
548 
564 
564 
564 
572 
580 
583 
583 
604 
610 
616 
619 
622 
645 
650 
655 
665 
665 
670 
678 
683 
690 
692 
694 
704 
706 
715 
720 

cals. 
+  47 
-     4 
-  57 
-  35 
+  53 
+  112 
-  41 
-  76 
+  83 
-  47 
+  34 
-51 
-  91 
-  89 
-     1 
-152 
-  53 
+  40 
+  119 
-  50 
-  79 
+  41 
-  24 
-129 
-  14 
+  86 
-  45 
-119 
+  29 
+  79 
-  47 
+  50 
+  48 

+  10 

-   21 
+  13 
+118 
+  59 
+  50 
+  59 
+  57 
+  31 
+116 

±   o 

-  51 

+  11.4 
-  0.9 
-10.9 
-  7.0 
+  12.6 
+31.1 
-  7.9 
-13.4 
+  19.8 
-  8.6 
+  7.2 
-  9.1 
-15.2 
-14.7 
-  0.2 
-22.2 
-  8.9 
+  7.9 
+26.7 
-  8.1 
-12.3 
+  7.7 
-  4.0 
-18.1 
-  2.3 
+16.6 
-  6.9 
-16.2 
+  4.9 
+14.5 
-  6.8 
+  8.3 
+  7.9 
+  1.5 
-  3.1 
+  2.0 
+21.1 
+  9.5 
+  7.8 
+  9.3 
+  8.9 
+  4.6 
+19.7 
+  0.0 
-6.6 

cals. 
429 
433 
423 
432 
438 
444 
482 
479 
445 
509 
489 
513 
485 
490 
502 
538 
544 
551 
550 
552 
523 
568 
573 
581 
563 
592 
611 
609 
620 
637 
629 
649 
673 
664 
633 
652 
679 
689 
712 
691 
712 
679 
689 
733 
721 

cals. 
+  16 
-  35 
-  99 
-  70 
+  19 
+  84 
-  40 
-  89 
+  26 
-  40 
+  15 
-  46 
-115 
-116 
-  26 
-148 
-  53 
+  43 
+105 
-  62 
-120 
+  37 
-  31 
-131 
-  34 
+  74 
-  44 
-126 
+  30 
+  94 
-  63 
+  49 
+  66 
+     9 
-  53 
-     5 
+119 
+  65 
+  72 
+  58 
+  75 
+     6 
+  99 
+  18 
-  50 

+  3.9 
-  7.5 
-19.0 
-13.9 
+  4.5 
+23.3 
-  7.7 
-15.7 
+  6.2 
-  7.3 
+  3.2 
-  8.2 
-19.2 
-19.1 
-  4.9 
-21.6 
-  8.9 
+  8.5 
+23.6 
-10.1 
-18.7 
+  7.0 
-  5.1 
-18.4 
-  5.7 
+14.3 
-  6.7 
-17.1 
+  5.1 
+17.3 
-  9.1 
+  8.2 
+  10.9 
+  1-4 
-  7.7 
-  0.8 
+21.3 
+  10.4 
+11.3 
+  9.2 
+  11.8 
+  0.9 
+16.8 
+  2.5 
-  6.5 

9^  mos. 

1  yr  3^  wks. 

9  mos.  1  wk  

9  mos.  1  wk.  ........ 
ll£  mos  

9.06 
9.19 
9.21 
9.22 
9.43 
9.67 
9.84 
10.1 
10.2 
10.6 
10.6 
10.6 
10.8 
11.0 
11.1 
11.1 
11.8 
12.0 
12.2 
12.3 
12.4 
13.2 
13.4 
13.6 
14.0 
14.0 
14.2 
14.5 
14.7 
15.0 
15.1 
15.2 
15.7 
15.8 
16.2 
16.4 

10  mos.  1  wk  

ll£  mos  
1  yr.  2  mos.  If  wks.  .  . 
1  yr.  2  mos.  3  wks.  .  .  . 
1  yr.  1  mo.  1  £  wks.  .  .  . 

9  mos  

yr.  5  mos  
1  yr.  9|  mos  
yr.  8|  mos  
2  yrs.  1  mo  

1  yr.  5£  mos  
yr.  8  mos.  3  J  wks.  .  . 
1  yr.  2  mos  
2  yrs.  4  mos  
2  yrs.  3  mos.  1  wk.  .  .  . 
2  yrs  2^  mos 

2  yrs.  9^  mos  
1  yr.  5  mos  
2  yra.  6  mos.  3  wks.  .  . 
3  yrs.  2  mos.  3  wks.  .  . 
3  yrs.  4j  mos  
3  yrs.  3  mos.  1  wk.  .  .  . 
3  yrs.  8  mos  
3  yrs.  9  mos.  3  wks.  .  . 
3  yrs.  10  mos.  3  wks.  . 
1  yr.  9  mos.  3  wks.  .  .  . 
5  yrs.  3  j  mos  
4  yrs.  3  mos.  3  wks.  .  . 
2  yrs.  4  mos  
4  yrs.  4  mos.  1  wk.  .  .  . 
3  yrs.  11  mos  

i  See  figure  27,  p.  142,  and  table  36,  p.  206. 


*  See  figure  39,  p.  164. 


PEEDICTION  OF  THE  BASAL  METABOLISM  OF  YOUTH.   201 


TABLE  34.— Comparison  of  the  actual  basal  metabolism  of  girls  with  that  predicted-  (a)  by  the 
curve  for  "Total  calories  referred  to  weight"?  and  (6)  by  the  curve  for  "Total  calories 
referred  to  surface  z — Continued. 


(a) 

(fe) 

to     (<0 

CO 

Heat  per  24  hrs. 

Heat  per  24  hrs. 

predicted  from 

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curve  for  "Total 

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calories  referred 

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11  yrs. 

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10  yrs.  9  mos.  3|  wks.  .  28.0     135.5    1.05 

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+  5.9|  lio02]  +  58  +  6.1 

234 

10  yrs.  5  mos.  3|  wks.  .   28.2     133.0.  1.03 

923  1,004 

+  81 

+  8.8      990;  +  67  +  7.3 

248 

11  yrs.  10  mos.  3  wks.  .  28.8     129.0,  1.04 

1,062  1,016 

-  46 

-  4.3      992  -  70  -  6.6 

233 

10  yrs.  5  mos.  2j  wks.  .   29.8  i  131.0   1.06 

896  1,040 

+144 

+16.1  1.016J  +120  +13.4 

251 

12  yrs.  2  mos  30.9 

138.5 

1.10 

1,012  1,068 

+  56 

+  5.5  1,050  +  38  +  3.8 

1See  figure  27,  p.  142,  and  table  36,  p.  206. 


2  See  figure  39,  p.  164. 


value  of  the  curves  for  total  calories  referred  to  weight  and  total 
calories  referred  to  measured  surface.  The  usual  scatter  of  points 
about  these  curves  is  such  as  to  indicate  a  reasonable  regularity  and 
suggest  the  possibilities  of  their  use  for  prediction  purposes.  As  we 
have  seen  with  boys,  exact  deductions  from  the  curves  themselves 
with  regard  to  the  accuracy  of  prediction  are  difficult  and  only  a 
mathematical  consideration  of  the  individual  differences  between  the 
predicted  and  actual  heat  of  individual  subjects  can  give  us  a  clear 
conception  as  to  their  accuracy.  Consequently,  a  table  has  been  pre- 
pared for  girls  (table  34)  in  which  are  given  the  values  for  heat  as 


202  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


actually  measured  and  as  predicted  from  the  curve  in  figure  27  (total 
calories  referred  to  weight)  and  likewise  the  heat  predicted  from  the 
curve  in  figure  39  (total  calories  referred  to  surface).  For  each  of  these 
series  of  values,  the  differences  between  the  predicted  and  actual  and 
the  percentage  differences  are  given. 

Considering  first  the  prediction  of  metabolism  from  the  curve  of 
total  calories  referred. to  weight,  we  find  the  plus  and  minus  signs  are 
fairly  equal  in  number,  as  would  be  expected  from  the  way  the  curve 
was  laid  on.  The  magnitude  of  the  differences  ranges  from  0  to  152 
calories,  but  since  the  children  vary  in  weight  from  2.7  to  30.9  kg., 
percentage  differences  alone  have  value  for  comparison  purposes. 
In  11  instances  the  error  of  prediction  is  20  per  cent  or  more;  but  10 
out  of  these  11  girls  weigh  10.6  kg.  or  less,  thereby  confirming  the  ob- 
servation made  with  boys  that  the  error  is  smaller  with  the  heavier 
children. 

TABLE  35. — Comparison  of  the  actual  basal  metabolism  of  girls  with  the  metabolism  predicted: 
(a)  from  body-weight,1  and  (b)  from  body-surface.2     (Average  values.3) 


Group. 

Basis 
of 
prediction. 

No. 
of 
girls. 

Actual 
heat 
per  24  hrs. 

Predicted 
heat 
per  24  hrs. 

Predicted 

less 
actual. 

Deviation 
of 
predicted 
from 
actual. 

All  girls 

Weight 

114 

cals. 
545 

cals. 
554 

cals. 
±46 

p.  ct. 
±97 

Below  10  kg  
Above  10  kg  
All  girls 

Do. 
Do. 

Surface 

58 
56 
114 

354 
743 
545 

357 
757 
544 

±41 
±52 

±48 

±11.8 
±  7.5 
±98 

Below  0.45  sq.  m.  .  .  . 
Above  0.45  sq.  m.  .  .  . 

Do. 
Do. 

49 
65 

315 

718 

312 

718 

±36 
±57 

±11.6 
±  8.5 

1  See  figure  27,  p.  142,  and  table  36,  p.  206 

8  Averages  obtained  from  data  in  table  34,  pp.  199  to  201. 


See  figure  39  p.  164. 


The  summaries  showing  the  average  differences  between  predicted 
and  actual  and  the  percentage  differences  for  girls  are  given  in  table  35. 
The  average  error  of  prediction  for  all  the  girls  on  this  basis  is  there 
given  as  ±9.7  per  cent.  Since  we  note  that  the  errors  are  greater  with 
the  earlier  weights,  the  girls  may  be  separated  into  those  weighing 
above  or  below  10  kg.  We  find  that  those  below  10  kg.  have  a  devia- 
tion of  ±11.8  per  cent  and  above  10  kg.  ±7.5  per  cent,  thus  furnishing 
a  mathematical  demonstration  of  our  conclusion  from  the  inspection 
of  the  figures  in  column  h  of  table  34  that  the  accuracy  of  the  prediction 
increases  with  the  increase  in  weight.  If  a  division  is  made  at  15  kg., 
as  was  done  for  the  boys,  the  percentage  deviation  for  the  girls  with 
this  or  a  higher  body-weight  is  ±6.1  per  cent. 

A  special  reason  for  separating  the  girls  at  10  kg.  is  based  upon  the 
fact  that  we  found  that  there  was  no  sexual  differentiation  in  the 
metabolism  of  boys  and  girls  up  to  the  weight  of  10  kg.,  so  on  this 


PREDICTION  OF  THE  BASAL  METABOLISM  OF  YOUTH.   203 

basis  alone  this  point  seems  to  be  a  justifiable  place  for  separation. 
From  a  comparison  of  the  figures  for  the  prediction  of  metabolism  from 
weight  for  boys  in  table  33,  it  will  be  seen  that  in  every  instance  the 
prediction  for  boys  is  materially  better  than  that  for  girls.  Thus, 
with  body-weights  of  less  than  10  kg.,  the  error  for  the  boys  in  the 
prediction  of  the  metabolism  was  ±8.7  per  cent,  and  for  the  girls 
±11.8  per  cent.  Above  10  kg.  the  metabolism  of  the  boys  was  pre- 
dicted with  an  error  of  ±6.3  per  cent  and  the  girls  ±7.5  per  cent. 
For  15  kg.  or  above,  it  was  ±5.8  per  cent  for  the  boys  and  ±6.1  per 
cent  for  the  girls.  It  should  be  emphasized  that  these  differences  are 
not  due  to  an  error  in  the  curve  (which  is  a  smoothed  curve  repre- 
senting all  our  measurements),  but  to  the  more  pronounced  physio- 
logical differentiation  with  children  of  the  lower  weights.  This  is 
particularly  the  case  with  children  in  the  first  months  of  life,  a  con- 
siderable number  of  whom  appear  on  our  charts. 

PREDICTED  HEAT  FROM  TOTAL  CALORIES  REFERRED  TO 
SURFACE  (GIRLS). 

While  our  analysis  of  the  prediction  of  the  metabolism  from  the 
surface  for  boys  gives  little  reason  to  expect  a  better  method  of  pre- 
diction for  girls  with  this  criterion,  it  is  necessary  to  analyze  carefully 
the  data  in  table  34  for  the  heat  predicted  on  this  basis. 

The  actual  differences  range  from  0  to  148  calories,  an  extremely 
wide  range;  but  again  reference  must  be  made  primarily  to  the  per- 
centage differences,  indicated  in  column  k,  for  purposes  of  comparison. 
With  11  subjects  the  prediction  has  an  error  of  20  per  cent  or  more, 
but  10  of  these  are  girls  with  a  body-weight  of  10.6  kg.  or  below, 
corresponding  to  approximately  0.50  square  meter  of  body-surface. 
Thus,  on  the  basis  of  surface  as  well  as  weight,  the  larger  children 
apparently  exhibit  less  errors  of  prediction  by  this  method  of  analysis. 

When  the  actual  averages  are  compared  (see  table  35),  we  find  that 
the  average  deviation  of  the  predicted  from  the  actual  measurement 
is  ±9.8  per  cent,  this  being  the  largest  general  deviation  by  our 
methods  of  prediction,  considering  the  boys  as  a  whole  and  the  girls 
as  a  whole.  This  error  in  prediction  is  also  slightly  higher  than  that 
found  on  the  basis  of  weight  and  confirms  the  deduction  made  from 
the  values  for  boys,  i.  e.,  that  the  prediction  made  from  surface  is  on 
the  whole  slightly  inferior  to  that  from  weight. 

Realizing  that  the  smaller  children,  i.  e.,  those  with  the  smaller  body- 
surface,  show  the  greater  proportion  of  large  deviations,  it  remains  to 
be  seen  whether  or  not  any  particular  area  will  give  the  better  predic- 
tion. As  with  boys,  a  body-surface  area  of  0.45  square  meter,  which 
corresponds  to  a  body-weight  of  approximately  10  kg.,  has  been 
selected  as  the  dividing-line.  According  to  table  35,  the  percentage 
deviation  for  the  girls  with  a  body-surface  area  below  0.45  square 


204     METABOLISM   AND   GROWTH   FROM   BIRTH   TO   PUBERTY. 

meter  is  ±11. 6  per  cent,  while  for  those  above  it  is  ±8.5  per  cent, 
showing  a  measurably  greater  error  with  the  smaller  children.  If, 
again,  we  use  for  the  arbitrary  dividing-line,  the  surface  area  of  0.65 
square  meter,  the  percentage  deviation  for  the  girls  of  this  surface  area 
or  over  is  ±6.8  per  cent,  as  compared  with  ±8.5  per  cent  on  the  basis 
of  0.45  square  meter. 

It  is  thus  seen  from  the  data  in  table  35  that  the  error  of  prediction 
with  girls  by  surface  is  slightly  better  with  the  smaller  children,  i.  e., 
those  below  10  kg.  and  below  0.45  square  meter,  than  is  the  prediction 
from  weight,  but  with  the  larger  girls  the  prediction  by  weight  is 
considerably  better  than  by  surface,  i.  e.,  ±7.5  per  cent  against  ±8.5 
per  cent. 

It  will  be  noted  that  in  table  34  we  have  omitted  figures  regard- 
ing the  prediction  of  the  metabolism  of  girls  by  the  adult  multiple- 
prediction  formula  of  Harris  and  Benedict.  The  formula  for  men, 
which  is  used  to  predict  the  metabolism  for  boys,  is  given  on  page  197 
of  this  report.  The  formula  for  women  differs  considerably  from 
that  for  men  in  that  the  first  term  is  large,  being  655. 0955. l  The  other 
terms  for  weight  and  stature  are  both  positive,  that  for  age  alone  being 
negative.  Consequently,  since  the  ages  are  all  small  with  girls,  with  a 
maximum  of  15  years,  the  only  negative  term  would  at  most  corre- 
spond to  not  far  from  70  calories.  As  this  formula  deals  only  with 
those  organisms  having  a  heat  prediction  of  not  less  than  700  or  800 
calories,  it  is  obviously  impossible  to  apply  the  formula  to  the  heat 
production  of  young  girls.  While  we  might  have  used  the  formula 
for  men  for  this  computation  and  thus  studied  the  relative  differences 
in  metabolism  between  boys  and  girls,  it  was  believed  to  be  unnecessary, 
as  our  several  charts  point  out  very  clearly  the  sexual  differentiation. 

The  application  of  the  formula  for  women  to  girls  is  fraught  with 
considerable  danger.  Throughout  the  biometrical  treatment  of  the 
basal  metabolism  of  women  and  men  by  Harris  and  Benedict,  it  was 
brought  out  repeatedly  that  no  method  at  present  available  makes  it 
possible  to  predict  the  metabolism  of  women  with  any  approach  to 
the  accuracy  of  the  prediction  for  men.  Although  in  the  biometric 
study  referred  to  approximately  100  women  were  included,  they  were 
by  no  means  so  harmonious  in  physical  type  as  were  the  men,  the 
correlation  of  stature  and  weight  being  on  the  whole  about  half  that 
for  men.  Unfortunately,  the  data  with  which  this  correlation  can  be 
compared  are  very  few,  comprising  generally  the  Cambridge  students, 
both  male  and  female,  studied  by  Pearson.2  With  these  students  a 
much  more  homogeneous  group  was  found,  since  the  correlation 
between  weight  and  height  with  the  female  students  was  considerably 
better  than  that  found  for  the  male  students.  With  the  men  included 

1  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  227. 

2  Pearson,  Proc.  Roy.  Soc.  Lorid..  1899,  66,  p.  26. 


PREDICTION   OF   THE   BASAL   METABOLISM   OF   YOUTH.       205 

in  the  Harris  and  Benedict  study,  the  partial  correlation  between 
weight  and  stature  corrected  for  constant  age  was  for  136  men  0.5772, 
while  for  103  women  it  was  but  0.2995.1  This  alone  shows  that  with 
the  women  the  correlation  between  height  and  weight  was  considerably 
lower  than  with  the  men,  thus  indicating  greater  irregularity  in  physical 
configuration  and  departure  from  an  average. 

PRACTICAL  VALUE  OF  THE  PREDICTION  OF  BASAL  METABOLISM. 

Prediction  factors  are  of  importance  in  that  it  is  highly  desirable, 
particularly  in  clinical  work,  to  have  some  conception  of  the  general 
trend  of  the  metabolism  of  children  of  a  definite  age  or  weight.  We 
believe  that  we  have  sufficiently  emphasized  in  all  of  our  charts  that 
the  scatter  or  dispersal  of  the  individual  points  is  so  great  as  to  necessi- 
tate great  caution  in  considering  that  any  particular  normal  child 
may  indicate  a  fixed  normal  metabolism,  to  which  all  other  normal 
children  of  the  same  age,  sex,  height,  and  weight  should  conform. 
This  is  far  from  the  case. 

But  if  due  cognizance  is  taken  of  the  probable  deviations  from  the 
general  trend,  the  curves  for  total  calories  referred  to  body-weight  and 
total  calories  referred  to  body-surface  may  be  considered  as  distinctly 
helpful  in  indicating  whether  or  not  there  is  great  diversity  from  the 
general  trend  with  children  having  any  particular  configuration  or 
any  particular  illness,  or  subsisting  upon  any  dietetic  regime  or  nutri- 
tional plane,  or  with  any  physiological  change  affecting  the  group. 

As  will  be  seen,  the  emphasis  in  this  discussion  is  laid  upon  the 
group.  It  is  clear  from  the  most  cursory  examination  of  our  several 
charts  that  the  individual  child  may  vary  greatly  from  the  average, 
and  hence  it  is  only  with  extreme  caution  that  deviation  may  be 
interpreted  as  being  of  pathological  or  abnormal  nature  with  any 
individual  child.  If  special  conditions  of  diet,  life,  or  pathological 
development  are  to  be  studied,  it  must  be  clearly  established  that  the 
special  conditions  result  in  the  deviation  from  the  general  trend  in  a 
considerable  number  of  instances  or  a  group.  With  these  cautions 
in  mind,  we  may  suggest  that  the  curves  given  in  figures  26  and  27 
may  be  used  directly  for  predicting  the  most  probable  basal  metab- 
olism of  a  quiet,  resting  boy  or  girl. 

To  assist  clinicians  in  rapid  estimations  of  these  predictions,  we  have 
prepared  a  table  (table  36)  giving  the  most  probable  heat  production 
for  each  half  kilogram  of  body-weight  for  both  boys  and  girls.  If  the 
weight  of  the  boy  or  girl  is  known,  the  physician  may  thus  read  directly 
from  table  36  the  predicted  basal  metabolism  for  a  child  of  this  weight 
and  compare  it  with  the  heat  actually  measured  to  note  if  the  measured 
values  are  aberrant  in  any  way.  Owing  to  the  effort  and  time  required 

i  Harris  and  Benedict,  Carnegie  Inst.  Wash.  Pub.  No.  279,  1919,  p.  59,  table  12. 


206  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 


for  making  the  calculations  of  the  body-surface  by  the  Du  Bois  method, 
it  seems  unwise  to  tabulate  the  changes  in  metabolism  for  each  tenth 
of  a  square  meter.  These  can  always  be  obtained  by  direct  inspection 
of  the  curves  in  figures  38  and  39  in  case  surface-area  measurements 
are  made. 

TABLE  36. — Basal  heat  production  of  boys  and  girls  per  24  hours  predicted  from  body-weight. 


Body- 
weight 
(with- 

Predicted 
heat. 

Body- 
weight 
(with- 

Predicted 
heat. 

Body- 
weight 
(with- 

Predicted 
heat. 

Body- 
weight 
(with- 

Predicted 
heat. 

out 
cloth- 
ing). 

Boys. 

Girls. 

out 
cloth- 
ing). 

Boys. 

Girls. 

out 
cloth- 
ing). 

Boys. 

Girls. 

out 
cloth- 
ing). 

Boys. 

Girls. 

kilos. 

cals. 

cals. 

kilos. 

cola. 

cals. 

kilos. 

cals. 

cals. 

kilos. 

cals. 

cals. 

2.5 

115 

110 

11.5 

607 

595 

20.5 

873 

818 

29.5 

1,103 

1,032 

3.0 

150 

150 

12.0 

625 

610 

21.0 

885 

830 

30.0 

1,115 

1,045 

3.5 

180 

185 

12.5 

643 

625 

21.5 

898 

842 

30.5 

1,127 

1,058 

4.0 

210 

220 

13.0 

660 

640 

22.0 

910 

855 

31.0 

1,140 

1,070 

4.5 

240 

253 

13.5 

678 

652 

22.5 

925 

867 

31.5 

,150 

1,080 

5.0 

270 

285 

14.0 

695 

665 

23.0 

940 

880 

32.0 

,160 

1,090 

5.5 

300 

318 

14.5 

710 

678 

23.5 

953 

890 

32.5 

,170 

6.0 

330 

350 

15.0 

725 

690 

24.0 

965 

900 

33.0 

,180 

6.5 

360 

377 

15.5 

740 

700 

24.5 

978 

915 

33.5 

,190 

7.0 

390 

405 

16.0 

755 

710 

25.0 

990 

930 

34.0 

,200 

7.5 

418 

432 

16.5 

768 

722 

25.5 

1,005 

940 

34.5 

,210 

8.0 

445 

460 

17.0 

780 

735 

26.0 

1,020 

950 

35.0 

,220 

8.5 

470 

480 

17.5 

793 

747 

26.5 

1,033 

962 

35.5 

1,230 

9.0 

495 

500 

18.0 

805 

760 

27.0 

1,045 

975 

36.0 

1,240 

9.5 

520 

520 

18.5 

818 

770 

27.5 

1,058 

987 

36.5 

1,248 

10.0 

545 

540 

19.0 

830 

780 

28.0 

1,070 

1,000 

37.0 

1,255 

10.5 

568 

560 

19.5 

845 

793 

28.5 

1,080 

1,010 

37.5 

1,265 

11.0 

590 

580 

20.0 

860 

805 

29.0 

1,090 

1,020 

38.0 

1,275 

24-HOUR  ENERGY  REQUIREMENTS  OF  GROWING  CHILDREN. 

With  all  of  these  children,  the  only  activity  possible  was  the  move- 
ment of  the  arms  and  legs  while  the  child  lay  on  a  bed  or  cot  inside 
the  respiration  chamber.  There  could  be  no  running  about  and  no 
external  muscular  work  performed.  An  earlier  discussion1  of  the 
possibilities  of  an  increased  metabolism  due  to  the  muscular  activity 
of  an  infant  in  the  lying  position  has  shown  that  on  the  average  a 
maximum  increase  in  metabolism  of  65  per  cent  (in  exceptional  cases 
of  over  200  per  cent)  may  be  obtained  as  a  result  of  vigorous  kicking 
and  convulsive  crying  on  the  part  of  a  new-born  infant. 

While  our  studies  were  primarily  for  an  investigation  of  the  basal 
metabolism,  and  consequently  the  greatest  degree  of  repose  was  sought 
by  every  possible  means,  we  incidentally  secured  a  considerable  amount 
of  data  with  regard  to  muscular  activity.  Certain  of  the  children  were 
restless,  so  much  so  that  the  observations  had  to  be  stopped.  With 
very  young  infants  there  was  at  tunes  crying,  but  with  all  these  condi- 
tions the  children  were  lying  in  bed.  Aside  from  the  gross  records  on 

1  Benedict  and  Talbot,  Carnegie  Inst.  Wash.  Pub.  No.  233,  1915,  p.  111. 


24-HOUR   ENERGY   REQUIREMENTS.  207 

the  kymograph,  to  which  we  have  arbitrarily  assigned  values  of  I  to  VI, 
the  statistics  of  these  periods  of  activity  can  have  little  quantitative 
value  to  other  observers,  and  accordingly  they  are  not  published  here. 
All  of  the  results  for  these  periods  have  been  gathered  together,  how- 
ever, and  certain  deductions  seem  justified  by  an  inspection  of  the 
data.  In  the  first  place,  the  very  great  increases  noted  with  new-born 
children  may  occasionally  be  obtained  with  children  up  to  the  age  of 
9  months,  but  the  average  of  65  per  cent  found  with  new-born  babies 
does  not  continue  after  the  first  few  weeks  of  life.  Subsequently, 
until  the  age  of  6  months,  the  average  increase  due  to  activity  may  be  as 
high  as  40  per  cent.  As  the  age  of  the  child  increases  and  voluntary 
muscular  control  becomes  more  possible,  the  increments  noted  by  us 
decrease  in  value,  until  after  7  years  of  age  an  increase  due  to  activity 
of  over  30  per  cent  of  the  basal  value  is  rarely  found.  This  obtains 
for  girls  as  well  as  for  boys. 

Two  important  points  stand  out  as  a  result  of  this  inspection  of  data : 
First,  that  the  younger  the  infant  the  greater  is  the  percentage  increase 
in  metabolism  during  lying  on  account  of  crying  and  active  movement 
of  the  body,  arms,  and  legs;  and  second,  that  with  the  older  children 
voluntary  control  has  so  increased  as  greatly  to  reduce  the  maximum 
activity. 

These  values  have  special  significance  in  that  they  throw  light  upon 
the  practical  use  of  the  basal  value  in  the  computation  of  the  total 
24-hour  requirement  of  the  child.  From  the  fact  that  in  our  experi- 
ments children  after  7  years  of  age  rarely  had  a  heat  production  more 
than  30  per  cent  above  the  basal  in  periods  of  restlessness  or  activity, 
we  feel  justified  in  concluding  that  the  basal  value  is  almost  synony- 
mous with  the  heat  production  of  children  over  7  years  of  age  while 
in  bed,  save  for  the  stimulating  effect  of  food.  Since  children  are  for 
the  most  part  anywhere  from  8  to  12  hours  of  the  day  in  bed,  this 
forms  an  important  quota  of  the  total  24-hour  requirement. 

Further  than  this  with  the  older  children  we  may  not  go.  The  great 
differences  in  muscular  activity  of  the  boy  or  girl  at  play,  differences 
which  are  fully  attested  by  recent  studies  of  the  food  consumption  in 
boys'  schools,1  shows  that  the  actual  caloric  output  during  the  waking 
period  and  when  the  children  are  actively  at  play  is  very  much  greater 
than  the  basal  output,  i.  e.,  that  obtained  when  the  child  is  in  bed 
resting  quietly. 

With  babies,  whose  time  for  the  most  part  is  spent  in  bed,  some- 
what more  definite  information  is  at  hand,  as  two  24-hour  experiments 
have  been  made  which  have  already  been  reported.2  With  one 
infant,  E.  L.,  2  months  and  3  weeks  old,  and  having  a  body-weight 
at  the  tune  of  observation  of  5.03  kg.,  the  basal  heat-output  per  24 

1  Gephart,  Boston  Med.  and  Surg.  Journ.,  1917,  176,  p.  17. 

2  Talbot,  Am.  Journ.  Diseases  of  Children,  1917,  14,  p.  25. 


208  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

hours  was  found  by  computation  of  results  in  minimum  periods  to  be 
285  calories.  The  child  was  22  hours  and  31  minutes  inside  the  respira- 
tion chamber.  The  total  heat-output,  calculated  on  the  basis  of  24 
hours,  was  372  calories,  or  an  increase  of  87  calories  (approximately 
30  per  cent)  over  basal.  The  second  child,  E.  S.,  weighed  at  the  time 
of  the  observation  5.76  kg.  and  was  6  months  and  1  week  old.  She 
was  for  23  hours  and  10  minutes  inside  the  respiration  chamber, 
giving  a  total  heat-output  per  24  hours  of  404  calories.  Computation 
of  the  basal  metabolism  by  the  selection  of  quiet  periods  gave  338 
calories,  the  increase  over  basal  being  66  calories  or  approximately 
20  per  cent. 

From  these  two  experiments,  therefore,  it  would  appear  that  al- 
though it  is  possible  for  young  children  to  have  percentage  increases 
over  the  basal  for  relatively  short  periods  of  60  or  70  per  cent,  or  even 
more,  the  total  24-hour  heat  production  on  the  average  may  be  taken 
as  not  far  from  25  per  cent  above  the  basal.  These  two  isolated  points 
at  the  ages  of  2  months  and  3  weeks  and  of  6  months  and  1  week  can 
give  only  a  general  hint  as  to  the  increase  in  the  24-hour  demand  over 
basal.  When  children  are  able  to  leave  the  crib  or  cot  and  actively 
exercise  by  creeping,  crawling,  and  walking  around,  especially  older 
children  when  running  and  playing,  the  increase  above  basal  becomes 
very  great,  and  our  own  observations  can  obviously  contribute  in  no 
wise  to  an  estimate  of  the  24-hour  demand  on  this  basis. 

The  proper  estimation  of  the  food  needs  of  growing  children  can 
probably  never  be  completely  and  satisfactorily  made  from  gaseous 
metabolism  experiments.  With  children,  with  whom  the  problem  of 
growth  plays  so  active  a  r61e,  one  must  supply  energy  not  only  for 
maintenance  and  for  juvenile  physical  activity,  but  likewise  energy 
for  growth.  Even  if  respiration-chamber  experiments  were  made  in 
which  an  accurate  measurement  was  made  of  the  entire  heat-output 
for  24  hours  of  a  number  of  individual  children  engaging  in  the  usual 
24-hour  day  activity,  there  still  would  be  the  growth  factor  to  be 
allowed  for.  In  any  complex  of  this  nature,  one  is  not  justified  in 
saying  that,  since  one  of  the  three  factors  is  difficult  of  estimation, 
the  others  can  not  be  satisfactorily  determined.  If  possible,  it  is 
important  to  determine  the  basal  needs  and  also  the  need  for  extra 
physical  activity. 

So  far  as  the  basal  value  is  concerned,  our  experiments,  we  believe, 
are  reasonably  conclusive.  So  far  as  the  extra  needs  are  concerned, 
our  data  supply  little  if  anything  of  value.  The  maximum  activities 
noted  with  children  lying  in  the  respiration  chamber  can,  with  children 
over  1£  or  2  years  of  age,  have  little  meaning.  Children  below  this 
age  are,  for  the  most  part,  lying  either  in  the  bed  or  crib,  and  conse- 
quently these  periods  of  maximum  activity  can  well  correspond  to 
those  occurring  in  the  life  of  an  ordinary  young  infant. 


24-HOUR  ENERGY   REQUIREMENTS. 


209 


Few  of  our  experiments  have  included  the  entire  24  hours,  and  we 
cite  only  two.  Accordingly  it  is  necessary  for  us  to  consider  observa- 
tions made  in  other  laboratories.  In  practically  all  the  experiments 
in  which  24-hour  periods  were  possible,  few  if  any  were  available  for 
comparison  with  our  basal  measurements,  but  they  are  of  prime  import- 
ance for  estimating  the  probable  total  24-hour  heat-output  for  very 
young  children.  We  have  collected  from  the  literature  a  number  of 
respiration-chamber  experiments  with  children  ranging  in  age  from 
1|  hours  to  9  months.  These  were  practically  all  carried  out  with  the 
Pettenkofer-Voit  type  of  apparatus  and  for  the  most  part  were  made 
in  Berlin.  The  data  for  these  experiments  are  given  in  table  37,  in 
which  is  recorded  the  heat-output  of  these  children  computed  on  the 
basis  of  per  kilogram  per  24  hours.  This  corresponds  very  closely, 
in  all  probability,  to  the  actual  heat  production,  but  does  not  corre- 
spond to  the  energy  needs,  since  the  amount  required  for  growth  is 
not  included.  Finally,  we  have  recorded  the  values  for  the  basal  heat 
per  kilogram  per  24  hours,  as  predicted  from  the  body-weight  curve 

TABLE  37. — Heat  production  per  kilogram  per  24  hours  of  normal  boys  studied  by  other 
investigators. 


Actual 

Heat 

heat 

per  kilo. 

Duration 

(com- 

per 

Investigator. 

of 
obser- 

Age of 
child. 

Body- 
weight. 

puted) 
per 

24  hrs. 
predicted 

Condition 
as  to  activity. 

vation. 

kilo. 

from 

per 

body- 

24  hrs. 

weight.1 

kilos. 

cafe. 

cols. 

f  12  hrs.  . 

ca.  1  J  hrs.  .  . 

3.1 

55 

50 

Absolutely 

Birk  and  Edelstein* 

I  18.6  hrs. 

ca.  1  day  .  .  . 

3.0 

55 

50 

quiet.' 
Not  stated. 

[22.2  hrs.  ca.  2  days.  . 

3.0? 

47 

50 

Do. 

Rubner  and  Heub- 

ner4   

6  days.  . 

9  wks. 

5.2 

67 

54 

Generally  quiet. 

Niemann*  

6  days.  . 

3|  mos 

5.1 

93 

54 

Generally  quiet; 

cried  some. 

Do. 

6  days.  . 

5  mos. 

5.9 

85 

55 

Quiet. 

Do. 

6  days.  . 

8  mos. 

5.6 

•89 

55 

Do. 

Do. 

17  days.  . 

9  mos. 

6.0 

•91 

55 

Do. 

Hellesen*  

3  days.  . 

5$  mos.     .  . 

6.7 

68 

56 

Do. 

Do  

3  days.  . 

6  mos.  .    .  . 

6.6 

74 

55 

Do. 

Rubner  and  Heub- 

ner8   

6  days.  . 

»7$  mos.  .  .  . 

7.6 

78 

58 

Generally   very 

quiet. 

Do.™.  .  . 

3  days.  . 

6j  mos.  .  .  . 

9.8 

68 

55 

Restless. 

Do  

1  day... 

5|  mos.  .  .  . 

9.6 

68 

55 

Do.» 

i  See  table  36,  p.  206. 

*  Birk  and  Edelstein,  Monatsschr.  f.  Kinderheilk.,  1910-11,  9,  p.  505. 

4  Rubner  and  Heubner,  Zeitschr.  f.  Biol.,  1898,  36,  p.  1. 

"Niemann,  Jahrb.  f.  Kinderheilk.,  1911,  74,  p.  22. 

6  Child  had  had  light  case  of  grippe  and  indigestion  previously. 

'  Hellesen,  Nord.  Med.  Arkiv,  1915,  48,  Nos.  14  and  18. 

»  Rubner  and  Heubner,  Zeitschr.  f.  Biol.,  1899,  38,  p.  315.  '  Girl. 

10  Rubner  and  Heubner,  Zeitschr.  f.  exp.  Pathol.  u.  Therapie,  1904-05,  1,  p.  1 


'Without  food. 


210  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

in  figure  26  (see  page  140)  for  weights  similar  to  those  noted  with  the 
children  studied  by  these  investigators. 

In  practically  every  instance  the  measured  heat,  as  computed  on  the 
24-hour  basis,  is  greater  than  the  predicted  heat.  The  one  exception 
is  the  value  found  on  the  third  day  of  the  observation  of  Birk  and 
Edelstein,  when  the  measured  heat  was  47  calories  per  kilogram  as 
compared  with  our  prediction  of  50  calories.  In  all  the  other  instances, 
values  very  much  higher  than  the  predicted  heat  are  found.  This 
would  be  expected,  however,  as  the  predicted  heat  represents  only  the 
basal  output,  while  the  measured  heat  includes  for  the  whole  24  hours 
not  only  the  basal  output,  but  the  heat  due  to  activity  when  it  exists, 
and  particularly  that  due  to  the  stimulus  from  food.  The  predicted 
heat  for  the  children  with  body-weights  of  3  to  10  kg.  ranges  from 
50  to  58  calories  per  kilogram  of  body-weight.  Using  55  calories  as 
an  approximate  average,  it  can  be  seen  that  the  measured  heat  is  very 
considerably  higher  in  most  cases,  although  the  values  of  Birk  and 
Edelstein  are  only  5  per  cent  higher,  on  the  average,  than  the  basal. 
With  Niemann's  infants,  the  measured  heat  is  nearly  70  per  cent 
higher  in  some  cases.  Even  when  the  protocols  indicate  that  the 
child  is  quiet,  we  find  great  increases  above  the  basal.  It  is  clear, 
therefore,  that  the  ordinary  24-hour  life  of  a  young  child  results  in  a 
heat  production  not  far  from  30  to  40  per  cent  above  basal,  a  value 
somewhat  in  excess  of  that  noted  in  our  two  experiments  previously 
cited.1 

Beyond  the  weight  of  10  kg.,  or  the  age  of  9  or  10  months,  very 
little  has  been  done  aside  from  the  classic  research  of  Sonden  and 
Tigerstedt2  and  that  of  Rubner.3  Professor  Carl  Tigerstedt,4  in  his 
monograph  on  the  food  intake  of  man,  has  collected  the  observations 
of  Hellstrom,  Rubner,  von  Willebrand,  and  Sonde"n  and  R.  Tiger- 
stedt, with  boys  ranging  from  9  to  14  years  of  age.  Although  he 
specifically  states  that  the  activity  was  to  a  high  degree  reduced,  no 
claim  is  made  for  basal  values  and  the  calculated  energy  output  is 
consequently  upon  a  "moderately  quiet"  basis.  The  data  thus  col- 
lected are  reproduced  here  in  table  38.  From  these  data,  Tigerstedt 
concludes  that  the  caloric  needs,  computed  on  the  basis  of  per  kilo- 
gram of  body-weight,  decrease  with  increasing  age.  He  also  finds  the 
same  result  when  the  computations  are  made  on  the  basis  of  body- 
surface  area,  although  this  is  not  shown  with  as  great  regularity  as  in 
the  case  of  weight.  As  heretofore  stated,  these  observations  were 
made  with  children  on  a  moderately  quiet  basis — that  is,  the  children 

1  Talbot,  Am.  Journ.  Diseases  of  Children,  1917,  14,  p.  25. 

*  Sond6n  and  Tigerstedt,  Skand.  Archiv  f.  Physioi.,  1895,  6,  p.  1. 

*  Rubner,  Beitrage  zur  Ernahrung  im  Knabenalter,  Berlin,  1902. 

4  Tigerstedt,  Carl,  Ueber  die  Nahrungszufuhr  dea  Menschen  in  ihrer  Abhangigkeit  von  Alter, 
Geschlecht  und  Beruf,  Helsingfors,  1915.  Also  published  in  Skand.  Archiv  f.  Physioi., 
1916,  34,  p.  151. 


24-HOUR   ENERGY   REQUIREMENTS. 


211 


were  inside  a  respiration  chamber  with  the  activity  considerably 
restricted. 

TABLE  38. — Twenty-four  hour  energy  requirements  of  boys. 


Age. 

Net  energy. 

Authority. 

Per  kg.                      Per  sq.  m. 

yrs. 
9 
10 
11 
12 
13 
14 

cals. 
56 
49 
50 
48 
37 
34 

cals. 
1,325 
1,233 
1,356 
1,277 
946 
862 

Tigerstedt,  Carl,  Ueber  die  Nahr- 
ungszufuhr  des  Menschen  in  ihrer 
Abhangigkeit  von  Alter,  Geschlecht 
und  Beruf,  Helsingfors,  1915,  p.  78. 
Also  published  in  Skand.  Archiv  f. 
Physiol.,  1916,  34,  p.  151. 

Thus  far  we  have  been  able  to  consider  children  at  two  distinct  levels 
of  activity:  (1)  basal,  i.  e.,  with  complete  muscular  repose;  (2)  with 
activity  restricted  by  the  confines  of  a  respiration  chamber.  With 
most  children  many  hours  in  the  day  are  spent  in  the  school-room. 
The  classic  research  of  Sonden  and  Tigerstedt  has  supplied  us  with 
information  as  to  the  energy  requirements  of  children  under  these 
conditions  of  modern  activity;  their  computations  were  made  by  Carl 
Tigerstedt1  on  the  basis  of  calories  per  kilogram  of  body-weight, 
assuming  that  1  gram  of  carbon  dioxide  corresponds  to  3  calories. 
Although  these  values  are  in  no  sense  basal,  they  represent  data 
obtained  with  an  approximately  uniform  muscular  activity  for  the 
various  ages.  The  results  for  the  age-period  within  the  range  of  our 
study  are  given  in  table  39,  and  show  clearly  a  decrease  in  metabolism 
per  kilogram  of  body-weight  from  7.9  years  to  15.5  years  of  age.  The 
values  all  lie  considerably  higher  than  not  only  the  basal,  but  also  the 
values  for  24-hour  chamber  experiments  given  in  table  38,  thus  showing 
on  the  whole  a  somewhat  greater  degree  of  activity  for  the  school 
children.  These  latter  values  more  nearly  approximate  the  true  24- 

TABLE  39. — Twenty-four  hour  energy  requirements  of  children  (Sond&n  and  Tigerstedt). 


Boys. 

Girls. 

Authority. 

Age. 

Heat  (computed) 
per  kilo, 
per  24  hrs. 

Age. 

Heat  (computed) 
per  kilo, 
per  24  hrs. 

yrs. 
7.9 
9.6 
10.5 
11.4 
12.5 
13.8 
14.5 
15.5 

cals. 
70 
75 
69 
66 
62 
62 
60 
50 

yrs. 
7.9 
9.9 
11.2 
12.2 
13.2 
14.0 
15.1 
15.6 

cals. 
70 
53 
52 
46 
43 
41 
35 
40 

Tigerstedt,  Carl,  Ueber  die 
Nahrungszufuhr  des  Mensch- 
en in  ihrer  Abhangigkeit  von 
Alter,  Geschlecht  und  Beruf, 
Helsingfors,  1915,  p.  79. 
See  also  Skand.  Arch.  f. 
Physiol.,  1916,  34,  p.  151. 

Tigerstedt,  Carl,  loc.  cit. 


212  METABOLISM  AND  GROWTH  FROM  BIRTH  TO  PUBERTY. 

hour  requirement  than  those  previously  discussed,  although  even  here 
the  children  were  not  studied  during  their  outdoor  or  extra-chamber 
activity. 

In  this  connection  a  study  may  be  made  of  the  curves  in  figures  33 
and  34  (page  152),  in  which  comparisons  are  made  between  the 
basal  metabolism  values  of  our  observations  and  the  values 
obtained  in  the  chamber  experiments  of  foreign  investigators  just 
discussed.  The  curves  representing  our  values  for  boys  from  7  to 
16  years  and  for  girls  from  7  to  14  years  are  obviously  projected  for 
the  sake  of  comparison,  as  material  for  the  later  ages  is  lacking.  The 
other  two  curves  on  the  boys'  chart  correspond  to  the  values  computed 
by  Carl  Tigerstedt  from  the  earlier  chamber  experiments  (table  38) 
and  the  extensive  series  of  observations  by  Sond6n  and  Tigerstedt  on 
school  children  ranging  in  age  from  8  to  23  years.  On  the  assumption 
that  the  school  children  would  have  a  varying  degree  of  activity 
which  would  be  measured  with  a  fair  degree  of  accuracy  by  the  carbon- 
dioxide  production  per  2  hours,  we  selected  for  the  plotting  of  the 
Sonden  and  Tigerstedt  curve  the  more  probable  minimum  carbon- 
dioxide  values  at  each  age,  discarding  those  that  were  obviously 
increased  by  activity.  (See  table  4,  page  10.)  Even  with  this  method 
of  eliminating  the  excessively  high  carbon-dioxide  production,  it  can 
be  seen  that  the  heat-output  obtained  with  school  children  was  very 
much  higher  than  either  the  values  found  in  the  24-hour  chamber 
experiments  included  in  table  38  or  (more  especially)  the  basal  values 
obtained  by  us.  Of  special  significance  are  the  two  experiments  of 
Sonde*n  and  Tigerstedt  with  two  sleeping  boys,  one  11  and  the  other 
12  years  of  age.  Their  results,  indicated  by  small  crosses,  lie  very 
near  our  basal  values. 

As  an  approximate  figure,  one  may  state  that  the  caloric  output  of 
school  children  in  the  school-room  would  be,  with  boys,  approximately 
75  per  cent  above  basal  (see  figure  33) ;  with  girls  the  increment  would 
be  more  nearly  50  per  cent  (see  figure  34).  Although  not  sufficiently 
accurate  for  use  in  computing  the  entire  24-hour  needs  of  growing 
children,  these  figures  are  of  distinct  value  in  interpreting  the  food 
needs  of  young  children  and  the  sum  total  of  the  day's  activities  of  a 
growing  child.  It  is  a  tribute  to  the  foresight  and  skill  of  the  Scandi- 
navian investigators  to  realize  that  now,  after  more  than  25  years, 
these  experiments  still  remain  of  definite  practical  value. 

To  sum  up,  we  have  in  these  two  measurements,  i.  e.,  the  basal 
value  and  the  value  for  school  children,  two  steps  in  the  important 
computation  of  the  24-hour  requirement.  The  basal  requirement  is 
substantially  the  energy  requirement  during  sojourn  in  bed,  this 
period  with  children  varying  from  8  to  10  or  even  12  hours.  The 
school  value  will  represent  the  requirement  for  5  to  6  hours  of  the  day. 
It  is  thus  possible  to  compute  the  total  energy  output  for  16  to  18 


24-HOUR   ENERGY   REQUIREMENTS.  213 

out  of  the  24  hours,  though  hi  the  remaining  6  hours  the  child  may  be 
occupied  in  such  vigorous  muscular  exercise  as  to  require  a  very  large 
correction  of  these  figures  before  the  ultimate  24-hour  computation 
may  even  be  approximated. 

To  explain  the  extraordinary  needs  of  growing  children  solely  upon 
the  basis  of  activity  is  somewhat  difficult.  The  activities  are,  it  is 
true,  enormous.  The  food  consumption  is  proportionately  great. 
The  deposition  of  tissue  must  be  provided  for  from  the  food  intake, 
and  this,  in  turn,  augmented  above  the  true  needs  for  simple  physical 
activity.  In  all  probability  a  factor  by  no  means  to  be  neglected  is 
the  stimulus  to  metabolism  resulting  from  the  ingestion  of  food.  As 
has  been  shown  in  the  report  of  an  earlier  research1  on  mixed  diets, 
especially  when  large  amounts  of  food  are  taken,  approximately  6  per 
cent  of  the  total  caloric  intake  is  eliminated  as  extra  heat,  which  has 
been  technically  termed  the  "cost  of  digestion." 

The  final  computation  of  the  total  24-hour  food-needs  or  heat-output 
of  a  growing  active  child  will  require  considerable  research.  The  heat- 
output  of  children  at  play  is  entirely  a  matter  of  speculation.  The 
determination  of  such  heat  production  is  by  no  means  a  technical 
impossibility;  indeed,  the  large  respiration  chamber  at  the  Nutrition 
Laboratory  is  designedly  constructed  for  the  measurement  of  exactly 
this  type  of  group  activities,  and  it  is  hoped  that  information  on  these 
points  may  ultimately  be  secured.  In  any  event,  it  is  clear  that  the 
caloric  needs  of  growing  children  are  very  much  greater  than  they  are 
commonly  supposed  to  be.  The  lesson  to  be  drawn  from  our  observa- 
tions on  private-school  children  (see  page  72)  is  that  outdoor  life  and 
physical  activity  contribute  towards  the  development  of  a  larger  indi- 
vidual, so  far  as  height,  i.  e.,  skeletal  growth,  is  concerned,  with  like- 
wise a  greater  weight  with  children  of  the  same  age.  But  it  is  probable 
that  even  these  children,  with  superior  surroundings  and  presumably 
better  medical  examination,  care,  and  dietetic  supply,  may  advan- 
tageously be  supplied  with  larger  amounts  of  food  than  they  at  present 
take.  One  could  infer,  therefore,  from  these  observations,  that, 
aside  from  the  possibilities  of  digestive  derangements,  it  would  be 
impossible  to  supply  the  growing  child  with  an  excessive  amount  of 
food.  Every  effort  may  legitimately  be  expended  to  secure  a  maximum 
skeletal  growth  and  the  development  of  children  above  so-called 
average  weight.  We  believe  that  our  investigation  shows  clearly  that 
the  average  weight  for  children  is  distinctly  below  the  ideal  or  physio- 
logically desirable  weight. 

1  Benedict  and  Carpenter,  Carnegie  Inst.  Wash.  Pub.  No.  261,  1918,  p.  341. 


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